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Duran B, Meziani ZE, Joosten S, Jones MK, Prasad S, Peng C, Armstrong W, Atac H, Chudakov E, Bhatt H, Bhetuwal D, Boer M, Camsonne A, Chen JP, Dalton MM, Deokar N, Diefenthaler M, Dunne J, El Fassi L, Fuchey E, Gao H, Gaskell D, Hansen O, Hauenstein F, Higinbotham D, Jia S, Karki A, Keppel C, King P, Ko HS, Li X, Li R, Mack D, Malace S, McCaughan M, McClellan RE, Michaels R, Meekins D, Paolone M, Pentchev L, Pooser E, Puckett A, Radloff R, Rehfuss M, Reimer PE, Riordan S, Sawatzky B, Smith A, Sparveris N, Szumila-Vance H, Wood S, Xie J, Ye Z, Yero C, Zhao Z. Determining the gluonic gravitational form factors of the proton. Nature 2023; 615:813-816. [PMID: 36991189 DOI: 10.1038/s41586-023-05730-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 01/13/2023] [Indexed: 03/31/2023]
Abstract
The proton is one of the main building blocks of all visible matter in the Universe1. Among its intrinsic properties are its electric charge, mass and spin2. These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering2. An example is the highly precise measurement of the electric charge radius of the proton6. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton7,8 from our measurement. We used a variety of models9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics12. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.
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Affiliation(s)
- B Duran
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - Z-E Meziani
- Physics Division, Argonne National Laboratory, Lemont, IL, USA.
- Department of Physics, Temple University, Philadelphia, PA, USA.
| | - S Joosten
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - M K Jones
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - S Prasad
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - C Peng
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - W Armstrong
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - H Atac
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - E Chudakov
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - H Bhatt
- Department of Physics & Astronomy, Mississippi State University, Mississippi State, MS, USA
| | - D Bhetuwal
- Department of Physics & Astronomy, Mississippi State University, Mississippi State, MS, USA
| | - M Boer
- Department of Physics, Virginia Polytechnic Institute & State University, Blacksburg, VA, USA
| | - A Camsonne
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - J-P Chen
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - M M Dalton
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - N Deokar
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - M Diefenthaler
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - J Dunne
- Department of Physics & Astronomy, Mississippi State University, Mississippi State, MS, USA
| | - L El Fassi
- Department of Physics & Astronomy, Mississippi State University, Mississippi State, MS, USA
| | - E Fuchey
- Department of Physics, University of Connecticut, Storrs, CT, USA
| | - H Gao
- Department of Physics, Duke University, Durham, NC, USA
| | - D Gaskell
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - O Hansen
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - F Hauenstein
- Department of Physics, Old Dominion University, Norfolk, VA, USA
| | - D Higinbotham
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - S Jia
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - A Karki
- Department of Physics & Astronomy, Mississippi State University, Mississippi State, MS, USA
| | - C Keppel
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - P King
- Department of Physics and Astronomy, Ohio University, Athens, OH, USA
| | - H S Ko
- CNRS/IN2P3, IJCLab Orsay, Université Paris-Saclay, Gif-sur-Yvette, France
| | - X Li
- Department of Physics, Duke University, Durham, NC, USA
| | - R Li
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - D Mack
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - S Malace
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - M McCaughan
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - R E McClellan
- Natural Sciences Department, Pensacola State College, Pensacola, FL, USA
| | - R Michaels
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - D Meekins
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - Michael Paolone
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - L Pentchev
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - E Pooser
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - A Puckett
- Department of Physics, University of Connecticut, Storrs, CT, USA
| | - R Radloff
- Department of Physics and Astronomy, Ohio University, Athens, OH, USA
| | - M Rehfuss
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - P E Reimer
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - S Riordan
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - B Sawatzky
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - A Smith
- Department of Physics, Duke University, Durham, NC, USA
| | - N Sparveris
- Department of Physics, Temple University, Philadelphia, PA, USA
| | - H Szumila-Vance
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - S Wood
- Experimental Nuclear Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA, USA
| | - J Xie
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - Z Ye
- Physics Division, Argonne National Laboratory, Lemont, IL, USA
| | - C Yero
- Department of Physics, Old Dominion University, Norfolk, VA, USA
| | - Z Zhao
- Department of Physics, Duke University, Durham, NC, USA
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2
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Li WB, Huber GM, Blok HP, Gaskell D, Horn T, Semenov-Tian-Shansky K, Pire B, Szymanowski L, Laget JM, Aniol K, Arrington J, Beise EJ, Boeglin W, Brash EJ, Breuer H, Chang CC, Christy ME, Ent R, Gibson EF, Holt RJ, Jin S, Jones MK, Keppel CE, Kim W, King PM, Kovaltchouk V, Liu J, Lolos GJ, Mack DJ, Margaziotis DJ, Markowitz P, Matsumura A, Meekins D, Miyoshi T, Mkrtchyan H, Niculescu I, Okayasu Y, Pentchev L, Perdrisat C, Potterveld D, Punjabi V, Reimer PE, Reinhold J, Roche J, Roos PG, Sarty A, Smith GR, Tadevosyan V, Tang LG, Tvaskis V, Volmer J, Vulcan W, Warren G, Wood SA, Xu C, Zheng X. Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction. Phys Rev Lett 2019; 123:182501. [PMID: 31763910 DOI: 10.1103/physrevlett.123.182501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/01/2019] [Indexed: 06/10/2023]
Abstract
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45 GeV^{2}, at W=2.21 GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45 GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.
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Affiliation(s)
- W B Li
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H P Blok
- VU University, NL-1081 HV Amsterdam, Netherlands
- NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, Netherlands
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Horn
- Catholic University of America, Washington, D.C. 20064, USA
| | - K Semenov-Tian-Shansky
- National Research Centre Kurchatov Institute: Petersburg Nuclear Physics Institute, RU-188300 Gatchina, Russia
- Saint Petersburg National Research Academic University of the Russian Academy of Sciences, RU-194021 St. Petersburg, Russia
| | - B Pire
- CPHT, CNRS, École Polytechnique, IP Paris, 91128-Palaiseau, France
| | - L Szymanowski
- National Centre for Nuclear Research (NCBJ), 02-093 Warsaw, Poland
| | - J-M Laget
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - K Aniol
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - J Arrington
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E J Beise
- University of Maryland, College Park, Maryland 20742, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33119, USA
| | - E J Brash
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - H Breuer
- University of Maryland, College Park, Maryland 20742, USA
| | - C C Chang
- University of Maryland, College Park, Maryland 20742, USA
| | - M E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E F Gibson
- California State University, Sacramento, California 95819, USA
| | - R J Holt
- Caltech, Pasadena, California 91125, USA
| | - S Jin
- Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - M K Jones
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C E Keppel
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Hampton University, Hampton, Virginia 23668, USA
| | - W Kim
- Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - P M King
- Ohio University, Athens, Ohio 45701, USA
| | - V Kovaltchouk
- Ontario Tech University, Oshawa, Ontario L1G 0C5, Canada
| | - J Liu
- Shanghai Jiao Tong University, Shanghai 200240, China
| | - G J Lolos
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - D J Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D J Margaziotis
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33119, USA
| | - A Matsumura
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Miyoshi
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - H Mkrtchyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - I Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | - Y Okayasu
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - L Pentchev
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Perdrisat
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - D Potterveld
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - P E Reimer
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33119, USA
| | - J Roche
- Ohio University, Athens, Ohio 45701, USA
| | - P G Roos
- University of Maryland, College Park, Maryland 20742, USA
| | - A Sarty
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - G R Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - V Tadevosyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - L G Tang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Hampton University, Hampton, Virginia 23668, USA
| | - V Tvaskis
- NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, Netherlands
- VU University, NL-1081 HV Amsterdam, Netherlands
| | - J Volmer
- VU University, NL-1081 HV Amsterdam, Netherlands
- DESY, Hamburg 22607, Germany
| | - W Vulcan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G Warren
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - S A Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Xu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - X Zheng
- University of Virginia, Charlottesville, Virginia 22904, USA
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3
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Ali A, Amaryan M, Anassontzis EG, Austregesilo A, Baalouch M, Barbosa F, Barlow J, Barnes A, Barriga E, Beattie TD, Berdnikov VV, Black T, Boeglin W, Boer M, Briscoe WJ, Britton T, Brooks WK, Cannon BE, Cao N, Chudakov E, Cole S, Cortes O, Crede V, Dalton MM, Daniels T, Deur A, Dobbs S, Dolgolenko A, Dotel R, Dugger M, Dzhygadlo R, Egiyan H, Ernst A, Eugenio P, Fanelli C, Fegan S, Foda AM, Foote J, Frye J, Furletov S, Gan L, Gasparian A, Gauzshtein V, Gevorgyan N, Gleason C, Goetzen K, Goncalves A, Goryachev VS, Guo L, Hakobyan H, Hamdi A, Han S, Hardin J, Huber GM, Hurley A, Ireland DG, Ito MM, Jarvis NS, Jones RT, Kakoyan V, Kalicy G, Kamel M, Kourkoumelis C, Kuleshov S, Kuznetsov I, Larin I, Lawrence D, Lersch DI, Li H, Li W, Liu B, Livingston K, Lolos GJ, Lyubovitskij V, Mack D, Marukyan H, Matveev V, McCaughan M, McCracken M, McGinley W, McIntyre J, Meyer CA, Miskimen R, Mitchell RE, Mokaya F, Nerling F, Ng L, Ostrovidov AI, Papandreou Z, Patsyuk M, Pauli P, Pedroni R, Pentchev L, Peters KJ, Phelps W, Pooser E, Qin N, Reinhold J, Ritchie BG, Robison L, Romanov D, Romero C, Salgado C, Schertz AM, Schumacher RA, Schwiening J, Seth KK, Shen X, Shepherd MR, Smith ES, Sober DI, Somov A, Somov S, Soto O, Stevens JR, Strakovsky II, Suresh K, Tarasov V, Taylor S, Teymurazyan A, Thiel A, Vasileiadis G, Werthmüller D, Whitlatch T, Wickramaarachchi N, Williams M, Xiao T, Yang Y, Zarling J, Zhang Z, Zhao G, Zhou Q, Zhou X, Zihlmann B. First Measurement of Near-Threshold J/ψ Exclusive Photoproduction off the Proton. Phys Rev Lett 2019; 123:072001. [PMID: 31491124 DOI: 10.1103/physrevlett.123.072001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/05/2019] [Indexed: 05/24/2023]
Abstract
We report on the measurement of the γp→J/ψp cross section from E_{γ}=11.8 GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67±0.39 GeV^{-2} at 10.7 GeV average energy. The LHCb pentaquark candidates P_{c}^{+} can be produced in the s channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions B(P_{c}^{+}→J/ψp) and cross sections σ(γp→P_{c}^{+})×B(P_{c}^{+}→J/ψp).
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Affiliation(s)
- A Ali
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - M Amaryan
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - E G Anassontzis
- National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - A Austregesilo
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - M Baalouch
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - F Barbosa
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Barlow
- Florida State University, Tallahassee, Florida 32306, USA
| | - A Barnes
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - E Barriga
- Florida State University, Tallahassee, Florida 32306, USA
| | - T D Beattie
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - V V Berdnikov
- National Research Nuclear University Moscow Engineering Physics Institute, Moscow 115409, Russia
| | - T Black
- University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33199, USA
| | - M Boer
- The Catholic University of America, Washington, D.C. 20064, USA
| | - W J Briscoe
- The George Washington University, Washington, D.C. 20052, USA
| | - T Britton
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - W K Brooks
- Universidad Técnica Federico Santa María, Casilla 110-V Valparaíso, Chile
| | - B E Cannon
- Florida State University, Tallahassee, Florida 32306, USA
| | - N Cao
- Institute of High Energy Physics, Beijing 100049, People's Republic of China
| | - E Chudakov
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Cole
- Arizona State University, Tempe, Arizona 85287, USA
| | - O Cortes
- The George Washington University, Washington, D.C. 20052, USA
| | - V Crede
- Florida State University, Tallahassee, Florida 32306, USA
| | - M M Dalton
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Daniels
- University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA
| | - A Deur
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Dobbs
- Florida State University, Tallahassee, Florida 32306, USA
| | - A Dolgolenko
- National Research Centre Kurchatov Institute, Institute for Theoretical and Experimental Physics, Moscow 117259, Russia
| | - R Dotel
- Florida International University, Miami, Florida 33199, USA
| | - M Dugger
- Arizona State University, Tempe, Arizona 85287, USA
| | - R Dzhygadlo
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - H Egiyan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - A Ernst
- Florida State University, Tallahassee, Florida 32306, USA
| | - P Eugenio
- Florida State University, Tallahassee, Florida 32306, USA
| | - C Fanelli
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Fegan
- The George Washington University, Washington, D.C. 20052, USA
| | - A M Foda
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - J Foote
- Indiana University, Bloomington, Indiana 47405, USA
| | - J Frye
- Indiana University, Bloomington, Indiana 47405, USA
| | - S Furletov
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - L Gan
- University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA
| | - A Gasparian
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - V Gauzshtein
- Tomsk State University, 634050 Tomsk, Russia
- Tomsk Polytechnic University, 634050 Tomsk, Russia
| | - N Gevorgyan
- A.I. Alikhanian National Science Laboratory (Yerevan Physics Institute), 0036 Yerevan, Armenia
| | - C Gleason
- Indiana University, Bloomington, Indiana 47405, USA
| | - K Goetzen
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - A Goncalves
- Florida State University, Tallahassee, Florida 32306, USA
| | - V S Goryachev
- National Research Centre Kurchatov Institute, Institute for Theoretical and Experimental Physics, Moscow 117259, Russia
| | - L Guo
- Florida International University, Miami, Florida 33199, USA
| | - H Hakobyan
- Universidad Técnica Federico Santa María, Casilla 110-V Valparaíso, Chile
| | - A Hamdi
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - S Han
- Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - J Hardin
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - A Hurley
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - D G Ireland
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - M M Ito
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - N S Jarvis
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - R T Jones
- University of Connecticut, Storrs, Connecticut 06269, USA
| | - V Kakoyan
- A.I. Alikhanian National Science Laboratory (Yerevan Physics Institute), 0036 Yerevan, Armenia
| | - G Kalicy
- The Catholic University of America, Washington, D.C. 20064, USA
| | - M Kamel
- Florida International University, Miami, Florida 33199, USA
| | - C Kourkoumelis
- National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - S Kuleshov
- Universidad Técnica Federico Santa María, Casilla 110-V Valparaíso, Chile
| | - I Kuznetsov
- Tomsk State University, 634050 Tomsk, Russia
- Tomsk Polytechnic University, 634050 Tomsk, Russia
| | - I Larin
- University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - D Lawrence
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D I Lersch
- Florida State University, Tallahassee, Florida 32306, USA
| | - H Li
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - W Li
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - B Liu
- Institute of High Energy Physics, Beijing 100049, People's Republic of China
| | - K Livingston
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - G J Lolos
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - V Lyubovitskij
- Tomsk State University, 634050 Tomsk, Russia
- Tomsk Polytechnic University, 634050 Tomsk, Russia
| | - D Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - H Marukyan
- A.I. Alikhanian National Science Laboratory (Yerevan Physics Institute), 0036 Yerevan, Armenia
| | - V Matveev
- National Research Centre Kurchatov Institute, Institute for Theoretical and Experimental Physics, Moscow 117259, Russia
| | - M McCaughan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - M McCracken
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - W McGinley
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - J McIntyre
- University of Connecticut, Storrs, Connecticut 06269, USA
| | - C A Meyer
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - R Miskimen
- University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - R E Mitchell
- Indiana University, Bloomington, Indiana 47405, USA
| | - F Mokaya
- University of Connecticut, Storrs, Connecticut 06269, USA
| | - F Nerling
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - L Ng
- Florida State University, Tallahassee, Florida 32306, USA
| | - A I Ostrovidov
- Florida State University, Tallahassee, Florida 32306, USA
| | - Z Papandreou
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - M Patsyuk
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - P Pauli
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - R Pedroni
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - L Pentchev
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - K J Peters
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - W Phelps
- The George Washington University, Washington, D.C. 20052, USA
| | - E Pooser
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - N Qin
- Northwestern University, Evanston, Illinois 60208, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33199, USA
| | - B G Ritchie
- Arizona State University, Tempe, Arizona 85287, USA
| | - L Robison
- Northwestern University, Evanston, Illinois 60208, USA
| | - D Romanov
- National Research Nuclear University Moscow Engineering Physics Institute, Moscow 115409, Russia
| | - C Romero
- Universidad Técnica Federico Santa María, Casilla 110-V Valparaíso, Chile
| | - C Salgado
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - A M Schertz
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - R A Schumacher
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - J Schwiening
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - K K Seth
- Northwestern University, Evanston, Illinois 60208, USA
| | - X Shen
- Institute of High Energy Physics, Beijing 100049, People's Republic of China
| | - M R Shepherd
- Indiana University, Bloomington, Indiana 47405, USA
| | - E S Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D I Sober
- The Catholic University of America, Washington, D.C. 20064, USA
| | - A Somov
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Somov
- National Research Nuclear University Moscow Engineering Physics Institute, Moscow 115409, Russia
| | - O Soto
- Universidad Técnica Federico Santa María, Casilla 110-V Valparaíso, Chile
| | - J R Stevens
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - I I Strakovsky
- The George Washington University, Washington, D.C. 20052, USA
| | - K Suresh
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - V Tarasov
- National Research Centre Kurchatov Institute, Institute for Theoretical and Experimental Physics, Moscow 117259, Russia
| | - S Taylor
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - A Teymurazyan
- University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | - A Thiel
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - G Vasileiadis
- National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - D Werthmüller
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - T Whitlatch
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | | | - M Williams
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - T Xiao
- Northwestern University, Evanston, Illinois 60208, USA
| | - Y Yang
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J Zarling
- Indiana University, Bloomington, Indiana 47405, USA
| | - Z Zhang
- Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - G Zhao
- Institute of High Energy Physics, Beijing 100049, People's Republic of China
| | - Q Zhou
- Institute of High Energy Physics, Beijing 100049, People's Republic of China
| | - X Zhou
- Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - B Zihlmann
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
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4
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Albayrak I, Mamyan V, Christy ME, Ahmidouch A, Arrington J, Asaturyan A, Bodek A, Bosted P, Bradford R, Brash E, Bruell A, Butuceanu C, Coleman SJ, Commisso M, Connell SH, Dalton MM, Danagoulian S, Daniel A, Day DB, Dhamija S, Dunne J, Dutta D, Ent R, Gaskell D, Gasparian A, Gran R, Horn T, Huang L, Huber GM, Jayalath C, Johnson M, Jones MK, Kalantarians N, Liyanage A, Keppel CE, Kinney E, Li Y, Malace S, Manly S, Markowitz P, Maxwell J, Mbianda NN, McFarland KS, Meziane M, Meziani ZE, Mills GB, Mkrtchyan H, Mkrtchyan A, Mulholland J, Nelson J, Niculescu G, Niculescu I, Pentchev L, Puckett A, Punjabi V, Qattan IA, Reimer PE, Reinhold J, Rodriguez VM, Rondon-Aramayo O, Sakuda M, Sakumoto WK, Segbefia E, Seva T, Sick I, Slifer K, Smith GR, Steinman J, Solvignon P, Tadevosyan V, Tajima S, Tvaskis V, Vulcan WF, Walton T, Wesselmann FR, Wood SA, Ye Z. Measurements of Nonsinglet Moments of the Nucleon Structure Functions and Comparison to Predictions from Lattice QCD for Q^{2}=4 GeV^{2}. Phys Rev Lett 2019; 123:022501. [PMID: 31386522 DOI: 10.1103/physrevlett.123.022501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/10/2019] [Indexed: 06/10/2023]
Abstract
We present extractions of the nucleon nonsinglet moments utilizing new precision data on the deuteron F_{2} structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world datasets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Moreover, recent exciting developments in lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach that first calculates the quark distributions directly before determining moments.
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Affiliation(s)
- I Albayrak
- Hampton University, Hampton, Virginia 23668, USA
- Catholic University of America, Washington, DC 20064, USA
| | - V Mamyan
- University of Chicago, Chicago, Illinois 60637, USA
| | - M E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - A Ahmidouch
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - J Arrington
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Asaturyan
- Yerevan Physics Institute, Yerevan 0036, Armenia
| | - A Bodek
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - P Bosted
- Department of Physics, College of William & Mary, Williamsburg, Virginia 23187, USA
| | - R Bradford
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E Brash
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - A Bruell
- DFG, German Research Foundation, Bonn 51170, Germany
| | - C Butuceanu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - S J Coleman
- Department of Physics, College of William & Mary, Williamsburg, Virginia 23187, USA
| | - M Commisso
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - S H Connell
- University of Johannesburg, Auckland Park 2006, Johannesburg, South Africa
| | - M M Dalton
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - S Danagoulian
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - A Daniel
- University of Houston, Houston, Texas 77004, USA
| | - D B Day
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - S Dhamija
- Florida International University, Miami, Florida 33199, USA
| | - J Dunne
- Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - D Dutta
- Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - R Ent
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D Gaskell
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - A Gasparian
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - R Gran
- Department of Physics, University of Minnesota-Duluth, Duluth, Minnesota 55812, USA
| | - T Horn
- Catholic University of America, Washington, DC 20064, USA
| | - Liting Huang
- Hampton University, Hampton, Virginia 23668, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - C Jayalath
- Hampton University, Hampton, Virginia 23668, USA
| | - M Johnson
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- Northwestern University, Evanston, Illinois 60208, USA
| | - M K Jones
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - N Kalantarians
- Virginia Union University, Richmond, Virginia 23220, USA
| | - A Liyanage
- Hampton University, Hampton, Virginia 23668, USA
| | - C E Keppel
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E Kinney
- University of Colorado, Boulder, Colorado 80309, USA
| | - Y Li
- Hampton University, Hampton, Virginia 23668, USA
| | - S Malace
- Duke University, Department of Physics, Box 90305, Durham, North Carolina 27708
| | - S Manly
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33199, USA
| | - J Maxwell
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - N N Mbianda
- University of Johannesburg, Auckland Park 2006, Johannesburg, South Africa
| | - K S McFarland
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - M Meziane
- Department of Physics, College of William & Mary, Williamsburg, Virginia 23187, USA
| | - Z E Meziani
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - G B Mills
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Mkrtchyan
- Yerevan Physics Institute, Yerevan 0036, Armenia
| | - A Mkrtchyan
- Yerevan Physics Institute, Yerevan 0036, Armenia
| | - J Mulholland
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - J Nelson
- Department of Physics, College of William & Mary, Williamsburg, Virginia 23187, USA
| | - G Niculescu
- James Madison University, Harrisonburg, Virginia 22801, USA
| | - I Niculescu
- James Madison University, Harrisonburg, Virginia 22801, USA
| | - L Pentchev
- Department of Physics, College of William & Mary, Williamsburg, Virginia 23187, USA
| | - A Puckett
- University of Connecticut, Storrs, Connecticut 06269, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - I A Qattan
- Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - P E Reimer
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33199, USA
| | | | | | - M Sakuda
- High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
| | - W K Sakumoto
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - E Segbefia
- Hampton University, Hampton, Virginia 23668, USA
| | - T Seva
- University of Zagreb, Zagreb 10000, Croatia
| | - I Sick
- University of Basel, CH-4056 Basel, Switzerland
| | - K Slifer
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - G R Smith
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Steinman
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - P Solvignon
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Tadevosyan
- Yerevan Physics Institute, Yerevan 0036, Armenia
| | - S Tajima
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - V Tvaskis
- University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada
| | - W F Vulcan
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Walton
- Hampton University, Hampton, Virginia 23668, USA
| | | | - S A Wood
- Thomas Jeferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - Zhihong Ye
- Hampton University, Hampton, Virginia 23668, USA
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5
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Armstrong W, Kang H, Liyanage A, Maxwell J, Mulholland J, Ndukum L, Ahmidouch A, Albayrak I, Asaturyan A, Ates O, Baghdasaryan H, Boeglin W, Bosted P, Brash E, Butuceanu C, Bychkov M, Carter P, Chen C, Chen JP, Choi S, Christy ME, Covrig S, Crabb D, Danagoulian S, Daniel A, Davidenko AM, Davis B, Day D, Deconinck W, Deur A, Dunne J, Dutta D, El Fassi L, Ellis C, Ent R, Flay D, Frlez E, Gaskell D, Geagla O, German J, Gilman R, Gogami T, Gomez J, Goncharenko YM, Hashimoto O, Higinbotham D, Horn T, Huber GM, Jones M, Jones MK, Kalantarians N, Kang HK, Kawama D, Keith C, Keppel C, Khandaker M, Kim Y, King PM, Kohl M, Kovacs K, Kubarovsky V, Li Y, Liyanage N, Luo W, Mack D, Mamyan V, Markowitz P, Maruta T, Meekins D, Melnik YM, Meziani ZE, Mkrtchyan A, Mkrtchyan H, Mochalov VV, Monaghan P, Narayan A, Nakamura SN, Nuruzzaman A, Pentchev L, Pocanic D, Posik M, Puckett A, Qiu X, Reinhold J, Riordan S, Roche J, Rondón OA, Sawatzky B, Shabestari M, Slifer K, Smith G, Soloviev LF, Solvignon P, Tadevosyan V, Tang L, Vasiliev AN, Veilleux M, Walton T, Wesselmann F, Wood S, Yao H, Ye Z, Zhang J, Zhu L. Revealing Color Forces with Transverse Polarized Electron Scattering. Phys Rev Lett 2019; 122:022002. [PMID: 30720291 DOI: 10.1103/physrevlett.122.022002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 10/18/2018] [Indexed: 06/09/2023]
Abstract
The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, d[over ˜]_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0 GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.
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Affiliation(s)
- W Armstrong
- Temple University, Philadelphia, Pennsylvania 19122, USA
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - H Kang
- Seoul National University, Seoul, South Korea
| | - A Liyanage
- Hampton University, Hampton, Virginia 23669, USA
| | - J Maxwell
- University of Virginia, Charlottesville, Virginia 22904, USA
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Mulholland
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - L Ndukum
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - A Ahmidouch
- North Carolina A&M State University, Greensboro, North Carolina 27411, USA
| | - I Albayrak
- Hampton University, Hampton, Virginia 23669, USA
| | - A Asaturyan
- Yerevan Physics Institute, 0036, Yerevan, Armenia
| | - O Ates
- Hampton University, Hampton, Virginia 23669, USA
| | - H Baghdasaryan
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33199, USA
| | - P Bosted
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E Brash
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - C Butuceanu
- University of Regina, Regina, Saskatchewan, S4S 0A2, Canada
| | - M Bychkov
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - P Carter
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - C Chen
- Hampton University, Hampton, Virginia 23669, USA
| | - J-P Chen
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Choi
- Seoul National University, Seoul, South Korea
| | - M E Christy
- Hampton University, Hampton, Virginia 23669, USA
| | - S Covrig
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D Crabb
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - S Danagoulian
- North Carolina A&M State University, Greensboro, North Carolina 27411, USA
| | - A Daniel
- Ohio University, Athens, Ohio 45701, USA
| | - A M Davidenko
- Kurchatov Institute-IHEP, Protvino, Moskva 123098, Russia
| | - B Davis
- North Carolina A&M State University, Greensboro, North Carolina 27411, USA
| | - D Day
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - W Deconinck
- William & Mary, Williamsburg, Virginia 23185, USA
| | - A Deur
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Dunne
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - D Dutta
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - L El Fassi
- Mississippi State University, Starkville, Mississippi 39759, USA
- Rutgers University, New Brunswick, New Jersey 08901, USA
| | - C Ellis
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D Flay
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - E Frlez
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - O Geagla
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - J German
- North Carolina A&M State University, Greensboro, North Carolina 27411, USA
| | - R Gilman
- Rutgers University, New Brunswick, New Jersey 08901, USA
| | - T Gogami
- Tohoku University, Tohoku, Miyagi Prefecture 980-8577, Japan
| | - J Gomez
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | | | - O Hashimoto
- Tohoku University, Tohoku, Miyagi Prefecture 980-8577, Japan
| | - D Higinbotham
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Horn
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan, S4S 0A2, Canada
| | - M Jones
- North Carolina A&M State University, Greensboro, North Carolina 27411, USA
| | - M K Jones
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - N Kalantarians
- University of Virginia, Charlottesville, Virginia 22904, USA
- Virginia Union University, Richmond, Virginia 23220, USA
| | - H-K Kang
- Seoul National University, Seoul, South Korea
| | - D Kawama
- Tohoku University, Tohoku, Miyagi Prefecture 980-8577, Japan
| | - C Keith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Keppel
- Hampton University, Hampton, Virginia 23669, USA
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - M Khandaker
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - Y Kim
- Seoul National University, Seoul, South Korea
| | - P M King
- Ohio University, Athens, Ohio 45701, USA
| | - M Kohl
- Hampton University, Hampton, Virginia 23669, USA
| | - K Kovacs
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - V Kubarovsky
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Y Li
- Hampton University, Hampton, Virginia 23669, USA
| | - N Liyanage
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - W Luo
- Lanzhou University, Lanzhou, Gansu Sheng, China
| | - D Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - V Mamyan
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33199, USA
| | - T Maruta
- Tohoku University, Tohoku, Miyagi Prefecture 980-8577, Japan
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - Y M Melnik
- Kurchatov Institute-IHEP, Protvino, Moskva 123098, Russia
| | - Z-E Meziani
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - A Mkrtchyan
- Yerevan Physics Institute, 0036, Yerevan, Armenia
| | - H Mkrtchyan
- Yerevan Physics Institute, 0036, Yerevan, Armenia
| | - V V Mochalov
- Kurchatov Institute-IHEP, Protvino, Moskva 123098, Russia
| | - P Monaghan
- Hampton University, Hampton, Virginia 23669, USA
| | - A Narayan
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - S N Nakamura
- Tohoku University, Tohoku, Miyagi Prefecture 980-8577, Japan
| | - A Nuruzzaman
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - L Pentchev
- William & Mary, Williamsburg, Virginia 23185, USA
| | - D Pocanic
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - M Posik
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - A Puckett
- University of Connecticut, Storrs, Connecticut 06269, USA
| | - X Qiu
- Hampton University, Hampton, Virginia 23669, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33199, USA
| | - S Riordan
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - J Roche
- Ohio University, Athens, Ohio 45701, USA
| | - O A Rondón
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - B Sawatzky
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - M Shabestari
- University of Virginia, Charlottesville, Virginia 22904, USA
- Mississippi State University, Starkville, Mississippi 39759, USA
| | - K Slifer
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - G Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - L F Soloviev
- Kurchatov Institute-IHEP, Protvino, Moskva 123098, Russia
| | - P Solvignon
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Tadevosyan
- Yerevan Physics Institute, 0036, Yerevan, Armenia
| | - L Tang
- Hampton University, Hampton, Virginia 23669, USA
| | - A N Vasiliev
- Kurchatov Institute-IHEP, Protvino, Moskva 123098, Russia
| | - M Veilleux
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - T Walton
- Hampton University, Hampton, Virginia 23669, USA
| | - F Wesselmann
- Xavier University, New Orleans, Louisiana 70125, USA
| | - S Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - H Yao
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Z Ye
- Hampton University, Hampton, Virginia 23669, USA
| | - J Zhang
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - L Zhu
- Hampton University, Hampton, Virginia 23669, USA
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6
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Fanelli C, Cisbani E, Hamilton DJ, Salmé G, Wojtsekhowski B, Ahmidouch A, Annand JRM, Baghdasaryan H, Beaufait J, Bosted P, Brash EJ, Butuceanu C, Carter P, Christy E, Chudakov E, Danagoulian S, Day D, Degtyarenko P, Ent R, Fenker H, Fowler M, Frlez E, Gaskell D, Gilman R, Horn T, Huber GM, de Jager CW, Jensen E, Jones MK, Kelleher A, Keppel C, Khandaker M, Kohl M, Kumbartzki G, Lassiter S, Li Y, Lindgren R, Lovelace H, Luo W, Mack D, Mamyan V, Margaziotis DJ, Markowitz P, Maxwell J, Mbianda G, Meekins D, Meziane M, Miller J, Mkrtchyan A, Mkrtchyan H, Mulholland J, Nelyubin V, Pentchev L, Perdrisat CF, Piasetzky E, Prok Y, Puckett AJR, Punjabi V, Shabestari M, Shahinyan A, Slifer K, Smith G, Solvignon P, Subedi R, Wesselmann FR, Wood S, Ye Z, Zheng X. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton. Phys Rev Lett 2015; 115:152001. [PMID: 26550716 DOI: 10.1103/physrevlett.115.152001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Indexed: 06/05/2023]
Abstract
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
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Affiliation(s)
- C Fanelli
- Dipartimento di Fisica, Università La Sapienza, Rome, Italy and INFN, Sezione di Roma, 00185 Rome, Italy
- INFN, Sezione di Roma, gruppo Sanità and Istituto Superiore di Sanità, 00161 Rome, Italy
| | - E Cisbani
- INFN, Sezione di Roma, gruppo Sanità and Istituto Superiore di Sanità, 00161 Rome, Italy
| | - D J Hamilton
- University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - G Salmé
- Dipartimento di Fisica, Università La Sapienza, Rome, Italy and INFN, Sezione di Roma, 00185 Rome, Italy
| | - B Wojtsekhowski
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - A Ahmidouch
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - J R M Annand
- University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - H Baghdasaryan
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - J Beaufait
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - P Bosted
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E J Brash
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - C Butuceanu
- University of Regina, Regina, Saskatchewan S4S OA2, Canada
| | - P Carter
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - E Chudakov
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Danagoulian
- North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - D Day
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - P Degtyarenko
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - H Fenker
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - M Fowler
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E Frlez
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - R Gilman
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855, USA
| | - T Horn
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S OA2, Canada
| | - C W de Jager
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - E Jensen
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - M K Jones
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - A Kelleher
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C Keppel
- Hampton University, Hampton, Virginia 23668, USA
| | - M Khandaker
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - M Kohl
- Hampton University, Hampton, Virginia 23668, USA
| | - G Kumbartzki
- Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855, USA
| | - S Lassiter
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - Y Li
- Hampton University, Hampton, Virginia 23668, USA
| | - R Lindgren
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - H Lovelace
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - W Luo
- Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China
| | - D Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - V Mamyan
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - D J Margaziotis
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33199, USA
| | - J Maxwell
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - G Mbianda
- University of Witwatersrand, Johannesburg, South Africa
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - M Meziane
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - J Miller
- University of Maryland, College Park, Maryland 20742, USA
| | - A Mkrtchyan
- Yerevan Physics Institute, Yerevan 375036, Armenia
| | - H Mkrtchyan
- Yerevan Physics Institute, Yerevan 375036, Armenia
| | - J Mulholland
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - V Nelyubin
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - L Pentchev
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C F Perdrisat
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - E Piasetzky
- University of Tel Aviv, Tel Aviv 6997801, Israel
| | - Y Prok
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - A J R Puckett
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - M Shabestari
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - A Shahinyan
- Yerevan Physics Institute, Yerevan 375036, Armenia
| | - K Slifer
- University of Virginia, Charlottesville, Virginia 22904, USA
| | - G Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - P Solvignon
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R Subedi
- University of Virginia, Charlottesville, Virginia 22904, USA
| | | | - S Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - Z Ye
- Hampton University, Hampton, Virginia 23668, USA
| | - X Zheng
- University of Virginia, Charlottesville, Virginia 22904, USA
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7
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Huber GM, Blok HP, Butuceanu C, Gaskell D, Horn T, Mack DJ, Abbott D, Aniol K, Anklin H, Armstrong C, Arrington J, Assamagan K, Avery S, Baker OK, Barrett B, Beise EJ, Bochna C, Boeglin W, Brash EJ, Breuer H, Chang CC, Chant N, Christy ME, Dunne J, Eden T, Ent R, Fenker H, Gibson EF, Gilman R, Gustafsson K, Hinton W, Holt RJ, Jackson H, Jin S, Jones MK, Keppel CE, Kim PH, Kim W, King PM, Klein A, Koltenuk D, Kovaltchouk V, Liang M, Liu J, Lolos GJ, Lung A, Margaziotis DJ, Markowitz P, Matsumura A, McKee D, Meekins D, Mitchell J, Miyoshi T, Mkrtchyan H, Mueller B, Niculescu G, Niculescu I, Okayasu Y, Pentchev L, Perdrisat C, Pitz D, Potterveld D, Punjabi V, Qin LM, Reimer PE, Reinhold J, Roche J, Roos PG, Sarty A, Shin IK, Smith GR, Stepanyan S, Tang LG, Tadevosyan V, Tvaskis V, van der Meer RLJ, Vansyoc K, Van Westrum D, Vidakovic S, Volmer J, Vulcan W, Warren G, Wood SA, Xu C, Yan C, Zhao WX, Zheng X, Zihlmann B. Separated response function ratios in exclusive, forward π(±) electroproduction. Phys Rev Lett 2014; 112:182501. [PMID: 24856691 DOI: 10.1103/physrevlett.112.182501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Indexed: 06/03/2023]
Abstract
The study of exclusive π(±) electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio RL=σL(π-)/σL(π+) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of RT=σT(π-)/σT(π+) from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to perturbative QCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive π(±) electroproduction on the deuteron at central Q(2) values of 0.6, 1.0, 1.6 GeV(2) at W=1.95 GeV, and Q(2)=2.45 GeV(2) at W=2.22 GeV. Here, we present the L and T cross sections, with emphasis on RL and RT, and compare them with theoretical calculations. Results for the separated ratio RL indicate dominance of the pion-pole diagram at low -t, while results for RT are consistent with a transition between pion knockout and quark knockout mechanisms.
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Affiliation(s)
- G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H P Blok
- VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands
| | - C Butuceanu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Horn
- Catholic University of America, Washington, DC 20064, USA
| | - D J Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D Abbott
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - K Aniol
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - H Anklin
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Florida International University, Miami, Florida 33119, USA
| | - C Armstrong
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - J Arrington
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K Assamagan
- Hampton University, Hampton, Virginia 23668, USA
| | - S Avery
- Hampton University, Hampton, Virginia 23668, USA
| | - O K Baker
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - B Barrett
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada
| | - E J Beise
- University of Maryland, College Park, Maryland 20742, USA
| | - C Bochna
- University of Illinois, Champaign, Illinois 61801, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33119, USA
| | - E J Brash
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H Breuer
- University of Maryland, College Park, Maryland 20742, USA
| | - C C Chang
- University of Maryland, College Park, Maryland 20742, USA
| | - N Chant
- University of Maryland, College Park, Maryland 20742, USA
| | - M E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - J Dunne
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Eden
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Norfolk State University, Norfolk, Virginia 23504, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - H Fenker
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E F Gibson
- California State University, Sacramento, California 95819, USA
| | - R Gilman
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - K Gustafsson
- University of Maryland, College Park, Maryland 20742, USA
| | - W Hinton
- Hampton University, Hampton, Virginia 23668, USA
| | - R J Holt
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - H Jackson
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S Jin
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - M K Jones
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C E Keppel
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - P H Kim
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - W Kim
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - P M King
- University of Maryland, College Park, Maryland 20742, USA
| | - A Klein
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - D Koltenuk
- University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - V Kovaltchouk
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - M Liang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Liu
- University of Maryland, College Park, Maryland 20742, USA
| | - G J Lolos
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - A Lung
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D J Margaziotis
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33119, USA
| | | | - D McKee
- New Mexico State University, Las Cruces, New Mexico 88003-8001, USA
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Mitchell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | | | - H Mkrtchyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - B Mueller
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - G Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | - I Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | | | - L Pentchev
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C Perdrisat
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - D Pitz
- DAPNIA/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette, France
| | - D Potterveld
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - L M Qin
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - P E Reimer
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33119, USA
| | - J Roche
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - P G Roos
- University of Maryland, College Park, Maryland 20742, USA
| | - A Sarty
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada
| | - I K Shin
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - G R Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Stepanyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - L G Tang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - V Tadevosyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - V Tvaskis
- VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands
| | | | - K Vansyoc
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - D Van Westrum
- University of Colorado, Boulder, Colorado 80309, USA
| | - S Vidakovic
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - J Volmer
- VU university, NL-1081 HV Amsterdam, The Netherlands and DESY, Hamburg, Germany
| | - W Vulcan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G Warren
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S A Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Xu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - C Yan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - W-X Zhao
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - X Zheng
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B Zihlmann
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and University of Virginia, Charlottesville, Virginia 22901, USA
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8
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Meziane M, Brash EJ, Gilman R, Jones MK, Luo W, Pentchev L, Perdrisat CF, Puckett AJR, Punjabi V, Wesselmann FR, Ahmidouch A, Albayrak I, Aniol KA, Arrington J, Asaturyan A, Ates O, Baghdasaryan H, Benmokhtar F, Bertozzi W, Bimbot L, Bosted P, Boeglin W, Butuceanu C, Carter P, Chernenko S, Christy E, Commisso M, Cornejo JC, Covrig S, Danagoulian S, Daniel A, Davidenko A, Day D, Dhamija S, Dutta D, Ent R, Frullani S, Fenker H, Frlez E, Garibaldi F, Gaskell D, Gilad S, Goncharenko Y, Hafidi K, Hamilton D, Higinbotham DW, Hinton W, Horn T, Hu B, Huang J, Huber GM, Jensen E, Kang H, Keppel C, Khandaker M, King P, Kirillov D, Kohl M, Kravtsov V, Kumbartzki G, Li Y, Mamyan V, Margaziotis DJ, Markowitz P, Marsh A, Matulenko Y, Maxwell J, Mbianda G, Meekins D, Melnik Y, Miller J, Mkrtchyan A, Mkrtchyan H, Moffit B, Moreno O, Mulholland J, Narayan A, Nedev S, Piasetzky E, Pierce W, Piskunov NM, Prok Y, Ransome RD, Razin DS, Reimer PE, Reinhold J, Rondon O, Shabestari M, Shahinyan A, Shestermanov K, Širca S, Sitnik I, Smykov L, Smith G, Solovyev L, Solvignon P, Subedi R, Suleiman R, Tomasi-Gustafsson E, Vasiliev A, Vanderhaeghen M, Veilleux M, Wojtsekhowski BB, Wood S, Ye Z, Zanevsky Y, Zhang X, Zhang Y, Zheng X, Zhu L. Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering. Phys Rev Lett 2011; 106:132501. [PMID: 21520982 DOI: 10.1103/physrevlett.106.132501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Indexed: 05/30/2023]
Abstract
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5 GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.
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Affiliation(s)
- M Meziane
- The College of William and Mary, Williamsburg, Virginia 23187, USA.
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9
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Malace SP, Paolone M, Strauch S, Albayrak I, Arrington J, Berman BL, Brash EJ, Briscoe B, Camsonne A, Chen JP, Christy ME, Chudakov E, Cisbani E, Craver B, Cusanno F, Ent R, Garibaldi F, Gilman R, Glamazdin O, Glister J, Higinbotham DW, Hyde-Wright CE, Ilieva Y, de Jager CW, Jiang X, Jones MK, Keppel CE, Khrosinkova E, Kuchina E, Kumbartzki G, Lee B, Lindgren R, Margaziotis DJ, Meekins D, Michaels R, Park K, Pentchev L, Perdrisat CF, Piasetzky E, Punjabi VA, Puckett AJR, Qian X, Qiang Y, Ransome RD, Saha A, Sarty AJ, Schulte E, Solvignon P, Subedi RR, Tang L, Tedeschi D, Tvaskis V, Udias JM, Ulmer PE, Vignote JR, Wesselmann FR, Wojtsekhowski B, Zhan X. Precise extraction of the induced polarization in the 4He(e,e'p)3H reaction. Phys Rev Lett 2011; 106:052501. [PMID: 21405386 DOI: 10.1103/physrevlett.106.052501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Indexed: 05/30/2023]
Abstract
We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation.
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Affiliation(s)
- S P Malace
- University of South Carolina, Columbia, South Carolina 29208, USA
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10
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Riordan S, Abrahamyan S, Craver B, Kelleher A, Kolarkar A, Miller J, Cates GD, Liyanage N, Wojtsekhowski B, Acha A, Allada K, Anderson B, Aniol KA, Annand JRM, Arrington J, Averett T, Beck A, Bellis M, Boeglin W, Breuer H, Calarco JR, Camsonne A, Chen JP, Chudakov E, Coman L, Crowe B, Cusanno F, Day D, Degtyarenko P, Dolph PAM, Dutta C, Ferdi C, Fernández-Ramírez C, Feuerbach R, Fraile LM, Franklin G, Frullani S, Fuchs S, Garibaldi F, Gevorgyan N, Gilman R, Glamazdin A, Gomez J, Grimm K, Hansen JO, Herraiz JL, Higinbotham DW, Holmes R, Holmstrom T, Howell D, de Jager CW, Jiang X, Jones MK, Katich J, Kaufman LJ, Khandaker M, Kelly JJ, Kiselev D, Korsch W, LeRose J, Lindgren R, Markowitz P, Margaziotis DJ, Beck SMT, Mayilyan S, McCormick K, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Ngo T, Nikolenko DM, Norum B, Pentchev L, Perdrisat CF, Piasetzky E, Pomatsalyuk R, Protopopescu D, Puckett AJR, Punjabi VA, Qian X, Qiang Y, Quinn B, Rachek I, Ransome RD, Reimer PE, Reitz B, Roche J, Ron G, Rondon O, Rosner G, Saha A, Sargsian MM, Sawatzky B, Segal J, Shabestari M, Shahinyan A, Shestakov Y, Singh J, Sirca S, Souder P, Stepanyan S, Stibunov V, Sulkosky V, Tajima S, Tobias WA, Udias JM, Urciuoli GM, Vlahovic B, Voskanyan H, Wang K, Wesselmann FR, Vignote JR, Wood SA, Wright J, Yao H, Zhu X. Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp. Phys Rev Lett 2010; 105:262302. [PMID: 21231649 DOI: 10.1103/physrevlett.105.262302] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Indexed: 02/05/2023]
Abstract
The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.
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Affiliation(s)
- S Riordan
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Paolone M, Malace SP, Strauch S, Albayrak I, Arrington J, Berman BL, Brash EJ, Briscoe B, Camsonne A, Chen JP, Christy ME, Chudakov E, Cisbani E, Craver B, Cusanno F, Ent R, Garibaldi F, Gilman R, Glamazdin O, Glister J, Higinbotham DW, Hyde-Wright CE, Ilieva Y, de Jager CW, Jiang X, Jones MK, Keppel CE, Khrosinkova E, Kuchina E, Kumbartzki G, Lee B, Lindgren R, Margaziotis DJ, Meekins D, Michaels R, Park K, Pentchev L, Perdrisat CF, Piasetzky E, Punjabi VA, Puckett AJR, Qian X, Qiang Y, Ransome RD, Saha A, Sarty AJ, Schulte E, Solvignon P, Subedi RR, Tang L, Tedeschi D, Tvaskis V, Udias JM, Ulmer PE, Vignote JR, Wesselmann FR, Wojtsekhowski B, Zhan X. Polarization transfer in the 4He(e,e'p)3H reaction at Q2=0.8 and 1.3 (GeV/c)2. Phys Rev Lett 2010; 105:072001. [PMID: 20868031 DOI: 10.1103/physrevlett.105.072001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Indexed: 05/29/2023]
Abstract
Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q{2}=0.8 and 1.3 (GeV/c){2} with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e,e'p) reaction, contradicting a relativistic distorted-wave approximation and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.
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Affiliation(s)
- M Paolone
- University of South Carolina, Columbia, South Carolina 29208, USA
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12
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Puckett AJR, Brash EJ, Jones MK, Luo W, Meziane M, Pentchev L, Perdrisat CF, Punjabi V, Wesselmann FR, Ahmidouch A, Albayrak I, Aniol KA, Arrington J, Asaturyan A, Baghdasaryan H, Benmokhtar F, Bertozzi W, Bimbot L, Bosted P, Boeglin W, Butuceanu C, Carter P, Chernenko S, Christy E, Commisso M, Cornejo JC, Covrig S, Danagoulian S, Daniel A, Davidenko A, Day D, Dhamija S, Dutta D, Ent R, Frullani S, Fenker H, Frlez E, Garibaldi F, Gaskell D, Gilad S, Gilman R, Goncharenko Y, Hafidi K, Hamilton D, Higinbotham DW, Hinton W, Horn T, Hu B, Huang J, Huber GM, Jensen E, Keppel C, Khandaker M, King P, Kirillov D, Kohl M, Kravtsov V, Kumbartzki G, Li Y, Mamyan V, Margaziotis DJ, Marsh A, Matulenko Y, Maxwell J, Mbianda G, Meekins D, Melnik Y, Miller J, Mkrtchyan A, Mkrtchyan H, Moffit B, Moreno O, Mulholland J, Narayan A, Nedev S, Piasetzky E, Pierce W, Piskunov NM, Prok Y, Ransome RD, Razin DS, Reimer P, Reinhold J, Rondon O, Shabestari M, Shahinyan A, Shestermanov K, Sirca S, Sitnik I, Smykov L, Smith G, Solovyev L, Solvignon P, Subedi R, Tomasi-Gustafsson E, Vasiliev A, Veilleux M, Wojtsekhowski BB, Wood S, Ye Z, Zanevsky Y, Zhang X, Zhang Y, Zheng X, Zhu L. Recoil polarization measurements of the proton electromagnetic form factor ratio to Q2 = 8.5 GeV2. Phys Rev Lett 2010; 104:242301. [PMID: 20873943 DOI: 10.1103/physrevlett.104.242301] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Indexed: 05/29/2023]
Abstract
Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this Letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5 GeV2. By extending the range of Q2 for which G(E)(p) is accurately determined by more than 50%, these measurements will provide significant constraints on models of nucleon structure in the nonperturbative regime.
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Affiliation(s)
- A J R Puckett
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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13
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Danagoulian A, Mamyan VH, Roedelbronn M, Aniol KA, Annand JRM, Bertin PY, Bimbot L, Bosted P, Calarco JR, Camsonne A, Chang CC, Chang TH, Chen JP, Choi S, Chudakov E, Degtyarenko P, de Jager CW, Deur A, Dutta D, Egiyan K, Gao H, Garibaldi F, Gayou O, Gilman R, Glamazdin A, Glashausser C, Gomez J, Hamilton DJ, Hansen JO, Hayes D, Higinbotham DW, Hinton W, Horn T, Howell C, Hunyady T, Hyde CE, Jiang X, Jones MK, Khandaker M, Ketikyan A, Kubarovsky V, Kramer K, Kumbartzki G, Laveissière G, Lerose J, Lindgren RA, Margaziotis DJ, Markowitz P, McCormick K, Meekins DG, Meziani ZE, Michaels R, Moussiegt P, Nanda S, Nathan AM, Nikolenko DM, Nelyubin V, Norum BE, Paschke K, Pentchev L, Perdrisat CF, Piasetzky E, Pomatsalyuk R, Punjabi VA, Rachek I, Radyushkin A, Reitz B, Roche R, Ron G, Sabatié F, Saha A, Savvinov N, Shahinyan A, Shestakov Y, Sirca S, Slifer K, Solvignon P, Stoler P, Tajima S, Sulkosky V, Todor L, Vlahovic B, Weinstein LB, Wang K, Wojtsekhowski B, Voskanyan H, Xiang H, Zheng X, Zhu L. Compton-scattering cross section on the proton at high momentum transfer. Phys Rev Lett 2007; 98:152001. [PMID: 17501338 DOI: 10.1103/physrevlett.98.152001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Indexed: 05/15/2023]
Abstract
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s=5-11 and -t=2-7 GeV2 with a statistical accuracy of a few percent. The scaling power for the s dependence of the cross section at fixed center-of-mass angle was found to be 8.0+/-0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.
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Affiliation(s)
- A Danagoulian
- University of Illinois, Urbana-Champaign, Illinois 61801, USA
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14
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Horn T, Aniol K, Arrington J, Barrett B, Beise EJ, Blok HP, Boeglin W, Brash EJ, Breuer H, Chang CC, Christy ME, Ent R, Gaskell D, Gibson E, Holt RJ, Huber GM, Jin S, Jones MK, Keppel CE, Kim W, King PM, Kovaltchouk V, Liu J, Lolos GJ, Mack DJ, Margaziotis DJ, Markowitz P, Matsumura A, Meekins D, Miyoshi T, Mkrtchyan H, Niculescu I, Okayasu Y, Pentchev L, Perdrisat C, Potterveld D, Punjabi V, Reimer P, Reinhold J, Roche J, Roos PG, Sarty A, Smith GR, Tadevosyan V, Tang LG, Tvaskis V, Vidakovic S, Volmer J, Vulcan W, Warren G, Wood SA, Xu C, Zheng X. Determination of the pion charge form factor at Q2=1.60 and 2.45 (GeV/c)2. Phys Rev Lett 2006; 97:192001. [PMID: 17155616 DOI: 10.1103/physrevlett.97.192001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Indexed: 05/12/2023]
Abstract
The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction.
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Affiliation(s)
- T Horn
- Department of Physics, University of Maryland, College Park, MD 20742, USA
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15
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Qattan IA, Arrington J, Segel RE, Zheng X, Aniol K, Baker OK, Beams R, Brash EJ, Calarco J, Camsonne A, Chen JP, Christy ME, Dutta D, Ent R, Frullani S, Gaskell D, Gayou O, Gilman R, Glashausser C, Hafidi K, Hansen JO, Higinbotham DW, Hinton W, Holt RJ, Huber GM, Ibrahim H, Jisonna L, Jones MK, Keppel CE, Kinney E, Kumbartzki GJ, Lung A, Margaziotis DJ, McCormick K, Meekins D, Michaels R, Monaghan P, Moussiegt P, Pentchev L, Perdrisat C, Punjabi V, Ransome R, Reinhold J, Reitz B, Saha A, Sarty A, Schulte EC, Slifer K, Solvignon P, Sulkosky V, Wijesooriya K, Zeidman B. Precision Rosenbluth measurement of the proton elastic form factors. Phys Rev Lett 2005; 94:142301. [PMID: 15904058 DOI: 10.1103/physrevlett.94.142301] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Indexed: 05/02/2023]
Abstract
We report the results of a new Rosenbluth measurement of the proton electromagnetic form factors at Q2 values of 2.64, 3.20, and 4.10 GeV2. Cross sections were determined by detecting the recoiling proton, in contrast to previous measurements which detected the scattered electron. Cross sections were determined to 3%, with relative uncertainties below 1%. The ratio mu(p)G(E)/G(M) was determined to 4%-8% and showed mu(p)G(E)/G(M) approximately 1. These results are consistent with, and much more precise than, previous Rosenbluth extractions. They are inconsistent with recent polarization transfer measurements of similar precision, implying a systematic difference between the techniques.
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Affiliation(s)
- I A Qattan
- Northwestern University, Evanston, Illinois 60208, USA
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16
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Gayou O, Aniol KA, Averett T, Benmokhtar F, Bertozzi W, Bimbot L, Brash EJ, Calarco JR, Cavata C, Chai Z, Chang CC, Chang T, Chen JP, Chudakov E, De Leo R, Dieterich S, Endres R, Epstein MB, Escoffier S, Fissum KG, Fonvieille H, Frullani S, Gao J, Garibaldi F, Gilad S, Gilman R, Glamazdin A, Glashausser C, Gomez J, Gorbenko V, Hansen JO, Higinbotham DW, Huber GM, Iodice M, de Jager CW, Jiang X, Jones MK, Kelly JJ, Khandaker M, Kozlov A, Kramer KM, Kumbartzki G, LeRose JJ, Lhuillier D, Lindgren RA, Liyanage N, Lolos GJ, Margaziotis DJ, Marie F, Markowitz P, McCormick K, Michaels R, Milbrath BD, Nanda SK, Neyret D, Papandreou Z, Pentchev L, Perdrisat CF, Piskunov NM, Punjabi V, Pussieux T, Quéméner G, Ransome RD, Raue BA, Roché R, Rvachev M, Saha A, Salgado C, Sirca S, Sitnik I, Strauch S, Todor L, Tomasi-Gustafsson E, Urciuoli GM, Voskanyan H, Wijesooriya K, Wojtsekhowski BB, Zheng X, Zhu L. Measurement of G(E(p))/G(M(p)) in e(-->)p---> e(-->)p to Q(2) = 5.6 GeV(2). Phys Rev Lett 2002; 88:092301. [PMID: 11863996 DOI: 10.1103/physrevlett.88.092301] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2001] [Indexed: 05/23/2023]
Abstract
The ratio of the electric and magnetic form factors of the proton G(E(p))/G(M(p)), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic e(-->)p---> e(-->)p reaction. The new data presented span the range 3.5< Q(2)< 5.6 GeV(2) and are well described by a linear Q(2) fit. Also, the ratio sqrt[Q(2)] F(2(p))/F(1(p)) reaches a constant value above Q(2) = 2 GeV(2).
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Affiliation(s)
- O Gayou
- College of William and Mary, Williamsburg, VA 23187, USA
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