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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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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Allen AH, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Neveling R, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, Van de Wiele J, van Oers WTH, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering. Phys Rev Lett 2007; 99:092301. [PMID: 17930999 DOI: 10.1103/physrevlett.99.092301] [Citation(s) in RCA: 2] [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: 05/11/2007] [Indexed: 05/25/2023]
Abstract
We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.
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Affiliation(s)
- D S Armstrong
- Department of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA
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3
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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Hawthorne Allen A, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, MacLachlan GA, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Nakos M, Neveling R, Niccolai S, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, van de Wiele J, van Oers W, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment. Phys Rev Lett 2005; 95:092001. [PMID: 16197209 DOI: 10.1103/physrevlett.95.092001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Indexed: 05/04/2023]
Abstract
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.
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Affiliation(s)
- D S Armstrong
- Department of Physics, College of William and Mary, Williamsburg, VA 23187, USA
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4
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Dohrmann F, Ahmidouch A, Armstrong CS, Arrington J, Asaturyan R, Avery S, Bailey K, Bitao H, Breuer H, Brown DS, Carlini R, Cha J, Chant N, Christy E, Cochran A, Cole L, Crowder J, Danagoulian S, Elaasar M, Ent R, Fenker H, Fujii Y, Gan L, Garrow K, Geesaman DF, Gueye P, Hafidi K, Hinton W, Juengst H, Keppel C, Liang Y, Liu JH, Lung A, Mack D, Markowitz P, Mitchell J, Miyoshi T, Mkrtchyan H, Mtingwa SK, Mueller B, Niculescu G, Niculescu I, Potterveld D, Raue BA, Reimer PE, Reinhold J, Roche J, Sarsour M, Sato Y, Segel RE, Semenov A, Stepanyan S, Tadevosian V, Tajima S, Tang L, Uzzle A, Wood S, Yamaguchi H, Yan C, Yuan L, Zeidman B, Zeier M, Zihlmann B. Angular distributions for (3,4)(Lambda)H bound states in the (3,4)He(e,e(')K+) reaction. Phys Rev Lett 2004; 93:242501. [PMID: 15697799 DOI: 10.1103/physrevlett.93.242501] [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: 07/14/2004] [Indexed: 05/24/2023]
Abstract
The (3,4)(Lambda)H and (4)(Lambda)H hypernuclear bound states have been observed for the first time in kaon electroproduction on (3,4)He targets. The production cross sections have been determined at Q(2)=0.35 GeV2 and W=1.91 GeV. For either hypernucleus the nuclear form factor is determined by comparing the angular distribution of the (3,4)He(e,e(')K+)(3,4)(Lambda)H processes to the elementary cross section 1H(e,e K+)Lambda on the free proton, measured during the same experiment.
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Affiliation(s)
- F Dohrmann
- Argonne National Laboratory, Argonne, IL 60439, USA.
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Warren G, Wesselmann F, Zhu H, McKee P, Savvinov N, Zeier M, Aghalaryan A, Ahmidouch A, Arenhövel H, Asaturyan R, Ben-Dayan I, Bloch F, Boeglin W, Boillat B, Breuer H, Brower J, Carasco C, Carl M, Carlini R, Cha J, Chant N, Christy E, Cole L, Coman L, Coman M, Crabb D, Danagoulian S, Day D, Duek K, Dunne J, Elaasar M, Ent R, Farrell J, Fatemi R, Fawcett D, Fenker H, Forest T, Garrow K, Gasparian A, Goussev I, Gueye P, Harvey M, Hauger M, Herrera R, Hu B, Jaegle I, Jones M, Jourdan J, Keith C, Kelly J, Keppel C, Khandaker M, Klein A, Klimenko A, Kramer L, Krusche B, Kuhn S, Liang Y, Lichtenstadt J, Lindgren R, Liu J, Lung A, Mack D, Maclachlan G, Markowitz P, McNulty D, Meekins D, Mitchell J, Mkrtchyan H, Nasseripour R, Niculescu I, Normand K, Norum B, Opper A, Piasetzky E, Pierce J, Pitt M, Prok Y, Raue B, Reinhold J, Roche J, Rohe D, Rondon O, Sacker D, Sawatzky B, Seely M, Sick I, Simicevic N, Smith C, Smith G, Steinacher M, Stepanyan S, Stout J, Tadevosyan V, Tajima S, Tang L, Testa G, Trojer R, Vlahovic B, Vulcan B, Wang K, Wells S, Woehrle H, Wood S, Yan C, Yanay Y, Yuan L, Yun J, Zihlmann B. Measurement of the electric form factor of the neutron at Q2=0.5 and 1.0 GeV2/c2. Phys Rev Lett 2004; 92:042301. [PMID: 14995367 DOI: 10.1103/physrevlett.92.042301] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Indexed: 05/24/2023]
Abstract
The electric form factor of the neutron was determined from measurements of the d-->(e-->,e'n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia (15ND3) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find G(n)(E)=0.0526+/-0.0033(stat)+/-0.0026(sys) and 0.0454+/-0.0054+/-0.0037 at Q(2)=0.5 and 1.0 (GeV/c)(2), respectively.
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Affiliation(s)
- G Warren
- Universität Basel, CH-4056 Basel, Switzerland
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6
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Gaskell D, Ahmidouch A, Ambrozewicz P, Anklin H, Arrington J, Assamagan K, Avery S, Bailey K, Baker OK, Beedoe S, Beise B, Breuer H, Brown DS, Carlini R, Cha J, Chant N, Cowley A, Danagoulian S, De Schepper D, Dunne J, Dutta D, Ent R, Gan L, Gasparian A, Geesaman DF, Gilman R, Glashausser C, Gueye P, Harvey M, Hashimoto O, Hinton W, Hofman G, Jackson C, Jackson HE, Keppel C, Kinney E, Koltenuk D, Kyle G, Lung A, Mack D, McKee D, Mitchell J, Mkrtchyan H, Mueller B, Niculescu G, Niculescu I, O'Neill TG, Papavassiliou V, Potterveld D, Reinhold J, Roos P, Sawafta R, Segel R, Stepanyan S, Tadevosyan V, Takahashi T, Tang L, Terburg B, Van Westrum D, Volmer J, Welch TP, Wood S, Yuan L, Zeidman B, Zihlmann B. Longitudinal electroproduction of charged pions from (1)H, (2)H, and (3)He. Phys Rev Lett 2001; 87:202301. [PMID: 11690468 DOI: 10.1103/physrevlett.87.202301] [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: 05/25/2001] [Indexed: 05/23/2023]
Abstract
Separated longitudinal and transverse cross sections for charged pion electroproduction from (1)H, (2)H, and (3)He were measured at Q(2) = 0.4 (GeV/c)(2) for two values of the invariant mass, W = 1.15 GeV and W = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil momenta significantly above the Fermi surface. The longitudinal cross section, if dominated by the pion-pole process, should be sensitive to nuclear pion currents. Comparisons of the longitudinal cross section target ratios to a quasifree calculation reveal a significant suppression in (3)He at W = 1.60 GeV. The W = 1.15 GeV results are consistent with simple estimates of the effect of nuclear pion currents, but are also consistent with pure quasifree production.
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Affiliation(s)
- D Gaskell
- Oregon State University, Corvallis, Oregon 97331, USA
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7
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Zhu H, Ahmidouch A, Anklin H, Arenhövel H, Armstrong C, Bernet C, Boeglin W, Breuer H, Brindza P, Brown D, Bültmann S, Carlini R, Chant N, Cowley A, Crabb D, Danagoulian S, Day DB, Eden T, Ent R, Farah Y, Fatemi R, Garrow K, Harris C, Hauger M, Honegger A, Jourdan J, Kaufmann M, Khandaker M, Kubon G, Lichtenstadt J, Lindgren R, Lourie R, Lung A, Mack D, Malik S, Markowitz P, McFarlane K, McKee P, McNulty D, Milanovich G, Mitchell J, Mkrtchyan H, Mühlbauer M, Petitjean T, Prok Y, Rohe D, Rollinde E, Rondon OA, Roos P, Sawafta R, Sick I, Smith C, Southern T, Steinacher M, Stepanyan S, Tadevosyan V, Tieulent R, Tobias A, Vulcan W, Warren G, Wöhrle H, Wood S, Yan C, Zeier M, Zhao J, Zihlmann B. Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2). Phys Rev Lett 2001; 87:081801. [PMID: 11497934 DOI: 10.1103/physrevlett.87.081801] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2001] [Indexed: 05/23/2023]
Abstract
We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).
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Affiliation(s)
- H Zhu
- Institute of Nuclear and Particle Physics, University of Virginia, Charlottesville, 22903, USA
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Volmer J, Abbott D, Anklin H, Armstrong C, Arrington J, Assamagan K, Avery S, Baker OK, Blok HP, Bochna C, Brash EJ, Breuer H, Chant N, Dunne J, Eden T, Ent R, Gaskell D, Gilman R, Gustafsson K, Hinton W, Huber GM, Jackson H, Jones MK, Keppel C, Kim PH, Kim W, Klein A, Koltenuk D, Liang M, Lolos GJ, Lung A, Mack DJ, McKee D, Meekins D, Mitchell J, Mkrtchyan H, Mueller B, Niculescu G, Niculescu I, Pitz D, Potterveld D, Qin LM, Reinhold J, Shin IK, Stepanyan S, Tadevosyan V, Tang LG, van der Meer RL, Vansyoc K, Van Westrum D, Vulcan W, Wood S, Yan C, Zhao WX, Zihlmann B. Measurement of the charged pion electromagnetic form factor. Phys Rev Lett 2001; 86:1713-1716. [PMID: 11290230 DOI: 10.1103/physrevlett.86.1713] [Citation(s) in RCA: 25] [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: 10/17/2000] [Indexed: 05/23/2023]
Abstract
Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.
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Affiliation(s)
- J Volmer
- NIKHEF, Amsterdam, The Netherlands
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