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Nefkens BMK, Prakhov S, Gårdestig A, Allgower CE, Bekrenev V, Briscoe WJ, Clajus M, Comfort JR, Craig K, Grosnick D, Isenhower D, Knecht N, Koetke D, Koulbardis A, Kozlenko N, Kruglov S, Lolos G, Lopatin I, Manley DM, Manweiler R, Marusić A, McDonald S, Olmsted J, Papandreou Z, Peaslee D, Phaisangittisakul N, Price JW, Ramirez AF, Sadler M, Shafi A, Spinka H, Stanislaus TDS, Starostin A, Staudenmaier HM, Supek I, Tippens WB. Test of charge conjugation invariance. Phys Rev Lett 2005; 94:041601. [PMID: 15783546 DOI: 10.1103/physrevlett.94.041601] [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: 09/10/2004] [Indexed: 05/24/2023]
Abstract
We report on the first determination of upper limits on the branching ratio (BR) of eta decay to pi0pi0gamma and to pi0pi0pi0gamma. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(eta-->pi0pi0gamma)<5 x 10(-4) at the 90% confidence level, in support of C invariance of isoscalar electromagnetic interactions of the light quarks. We have also measured BR(eta-->pi0pi0pi0gamma)<6 x 10(-5) at the 90% confidence level, in support of C invariance of isovector electromagnetic interactions.
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Affiliation(s)
- B M K Nefkens
- University of California Los Angeles, Los Angeles, California 90095-1547, USA
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Craig K, Comfort JR, Allgower CE, Bekrenev V, Berger E, Briscoe WJ, Clajus M, Draper B, Grosnick D, Isenhower D, Knecht N, Koetke D, Koulbardis A, Kozlenko N, Kruglov S, Lolos GJ, Lopatin I, Manley DM, Manweiler R, Marusić A, McDonald S, Nefkens BMK, Olmsted J, Papandreou Z, Peaslee D, Phaisangittisakul N, Prakhov S, Price JW, Pulver M, Ramirez AF, Sadler ME, Shafi A, Spinka H, Stanislaus S, Starostin A, Supek I, Staudenmaier HM, Tippens WB. Dynamics of the pi(-)p-->pi(0)pi(0)n reaction for p(pi(-))<750 MeV/c. Phys Rev Lett 2003; 91:102301. [PMID: 14525473 DOI: 10.1103/physrevlett.91.102301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2003] [Indexed: 05/24/2023]
Abstract
Data are presented for the reaction pi(-)p-->pi(0)pi(0)n in the range from threshold to p(pi(-))=750 MeV/c. The systematics of the data and multipole analyses are examined for sensitivity to a f(0)(600) ("sigma") meson. A one-pion-exchange mechanism is found to be very weak, or absent. The reaction appears to become dominated by sequential pi(0) decays through the Delta(1232) resonance as the beam momentum increases, along with substantial interference effects from several competing mechanisms.
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Affiliation(s)
- K Craig
- Arizona State University, Tempe, Arizona 85287-1504, USA
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Tippens WB, Prakhov S, Allgower CE, Bekrenev V, Berger E, Briscoe WJ, Clajus M, Comfort JR, Craig K, Efendiev A, Grosnick D, Holstein BR, Huber GM, Isenhower D, Knecht N, Koetke D, Koulbardis A, Kozlenko N, Kruglov S, Lolos GJ, Lopatin I, Manley DM, Marusić A, Manweiler R, McDonald S, Nefkens BM, Olmsted J, Papandreou Z, Phaisangittisakul N, Price JW, Pulver M, Ramirez AF, Sadler ME, Shafi A, Spinka H, Stanislaus S, Starostin A, Staudenmaier HM. Determination of the quadratic slope parameter in eta-->3pi(0) decay. Phys Rev Lett 2001; 87:192001. [PMID: 11690403 DOI: 10.1103/physrevlett.87.192001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2001] [Indexed: 05/23/2023]
Abstract
We have determined the quadratic slope parameter alpha for eta-->3pi(0) to be alpha = -0.031(4) from a 99% pure sample of 10(6)eta-->3pi(0) decays produced in the reaction pi(-)p-->n(eta) close to the eta threshold using the Crystal Ball detector at the AGS. The result is four times more precise than the present world data and disagrees with current chiral perturbation theory calculations by about four standard deviations.
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Affiliation(s)
- W B Tippens
- University of California, Los Angeles, Los Angeles, California 90095-1547
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Starostin A, Staudenmaier HM, Allgower CE, Bekrenev V, Berger E, Briscoe WJ, Clajus M, Comfort JR, Craig K, Grosnick D, Isenhower D, Knecht N, Koetke D, Koulbardis A, Kozlenko N, Kruglov S, Kycia T, Lolos G, Lopatin I, Manley DM, Manweiler B, Marusić A, McDonald S, Nefkens BM, Olmsted J, Papandreou Z, Peaslee D, Peterson RJ, Phaisangittisakul N, Prakhov S, Pulver M, Ramirez AF, Sadler M, Shafi A, Slaus I, Spinka H, Stanislaus S, Supek I, Tippens WB. Measurement of pi(0)pi(0) production in the nuclear medium by pi(-) interactions at 0.408 GeV/c. Phys Rev Lett 2000; 85:5539-5542. [PMID: 11136041 DOI: 10.1103/physrevlett.85.5539] [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: 05/01/2000] [Indexed: 05/23/2023]
Abstract
We report on an investigation of the (pi(-),pi(0)pi(0)) reaction by means of measurements of the pi(0)pi(0) invariant mass distributions from pi(-) interactions on H, D, C, Al, and Cu targets at p(pi(-)) = 0.408 GeV/c. The sharp, strong peak in the pi(+)pi(-) invariant mass near 2m(pi) reported by the CHAOS Collaboration is not seen in our pi(0)pi(0) data. However, we do observe a change in the shape of the pi(0)pi(0) invariant mass spectrum for the different targets, indicating that the pi(0)pi(0) interaction diminishes in the nuclear medium as represented by nuclei D, C, Al, and Cu, compared to hydrogen.
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Affiliation(s)
- A Starostin
- University of California Los Angeles, Los Angeles, California 90095-1547, USA
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Prakhov S, Tippens WB, Allgower C, Bekrenev V, Berger E, Briscoe WJ, Clajus M, Comfort JR, Craig K, Grosnick D, Huber GM, Isenhower D, Knecht N, Koetke D, Koulbardis A, Kozlenko N, Kruglov S, Kycia T, Lolos GJ, Lopatin I, Manley DM, Marusic A, Manweiler R, McDonald S, Nefkens BM, Olmsted J. Search for the CP forbidden decay eta-->4pi(0). Phys Rev Lett 2000; 84:4802-4805. [PMID: 10990802 DOI: 10.1103/physrevlett.84.4802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/1999] [Indexed: 05/23/2023]
Abstract
We report the first determination of the upper limit for the branching ratio of the CP forbidden decay eta-->4pi(0). No events were observed in a sample of 3.0x10(7) eta decays. The experiment was performed with the Crystal Ball multiphoton spectrometer installed in a separated pi(-) beam at the AGS (Alternating Gradient Synchrotron). At the 90% confidence limit, B(eta-->4pi(0))</=6. 9x10(-7).
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Affiliation(s)
- S Prakhov
- University of California, Los Angeles, Los Angeles, California 90095-1547, USA
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Campbell JH, Charlton G, Engelmann R, Glasser RG, Jaeger K, Mann WA, Oren Y, Peeters P, Whitmore J, Fu C, Rubin HA, Swansson D, Koetke D. Study of Inclusiveγandπ0Production in 12.4-GeV/cppInteractions. Int J Clin Exp Med 1973. [DOI: 10.1103/physrevd.8.3824] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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