排序方式： 共有5条查询结果，搜索用时 15 毫秒
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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 《Physical review letters》2000,84(21):4802-4805
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))相似文献
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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 BM 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;Crystal Ball Collaboration 《Physical review letters》2003,91(10):102301
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. 相似文献
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Nefkens BM 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 TD Starostin A Staudenmaier HM Supek I Tippens WB;Crystal Ball Collaboration 《Physical review letters》2005,94(4):041601
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. 相似文献
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N. G. Kozlenko V. V. Abaev V. S. Bekrenev S. P. Kruglov A. A. Koulbardis I. V. Lopatin A. B. Starostin B. Draper S. Hayden J. Huddleston D. Isenhower C. Robinson M. Sadler C. Allgower R. Cadman H. Spinka J. Comfort K. Craig A. Ramirez T. Kycia M. Clajus A. Marusic S. McDonald B. M. K. Nefkens N. Phaisangittisakul S. Prakhov J. W. Price W. B. Tippens J. Peterson W. J. Briscoe A. Shafi I. I. Strakovsky H. Staudenmaier D. M. Manley J. Olmsted D. Peaslee N. Knecht G. Lolos Z. Papandreou I. Supek I. Slaus A. Gibson D. Grosnic D. Koetke R. Manweiler S. Stanislaus 《Physics of Atomic Nuclei》2003,66(1):110-113
The first results obtained in 1998 by the Crystal Ball collaboration from a measurement of the total and differential cross sections for the reaction π ? p → ηn are presented. These new experimental results for the total cross sections are compared with the predictions of the K-matrix model for pion-nucleon scattering. The angular distribution at momenta near the reaction threshold (685 MeV/c) is determined by the S-wave contribution. The P-wave contribution begins to manifest itself from a momentum of 720 MeV/c. 相似文献
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