Measurement of the Slope Parameter $α$ for the $η\to 3π^0$ decay with the Crystal Ball detector at the Mainz Microtron (MAMI-C)
S. Prakhov, B. M. K. Nefkens, P. Aguar-Bartolome, L. K. Akasoy, J. R. M. Annand, H. J. Arends, K. Bantawa, R. Beck, V. Bekrenev, H. Berghauser, B. Boillat, A. B… 展开作者
S. Prakhov, B. M. K. Nefkens, P. Aguar-Bartolome, L. K. Akasoy, J. R. M. Annand, H. J. Arends, K. Bantawa, R. Beck, V. Bekrenev, H. Berghauser, B. Boillat, A. Braghieri, D. Branford, W. J. Briscoe, J. Brudvik, S. Cherepnya, R. F. B. Codling, E. J. Downie, P. Drexler, L. V. Fil'kov, D. I. Glazier, R. Gregor, E. Heid, D. Hornidge, O. Jahn, T. C. Jude, V. L. Kashevarov, J. D. Kellie, R. Kondratiev, M. Korolija, M. Kotulla, A. Koulbardis, D. Krambrich, S. Kruglov, B. Krusche, M. Lang, V. Lisin, K. Livingston, I. J. D. MacGregor, Y. Maghrbi, D. M. Manley, M. Martinez, J. C. McGeorge, E. F. McNicoll, D. Mekterovic, V. Metag, S. Micanovic, A. Nikolaev, R. Novotny, M. Ostrick, P. B. Otte, P. Pedroni, F. Pheron, A. Polonski, J. Robinson, G. Rosner, M. Rost, T. Rostomyan, S. Schumann, M. H. Sikora, D. I. Sober, A. Starostin, I. M. Suarez, I. Supek, C. M. Tarbert, M. Thiel, A. Thomas, M. Unverzagt, D. P. Watts, I. Zamboni, F. Zehr
The dynamics of the $η\to 3π^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $η$-meson production. The analysis of $3 \times 10^6$ $γp \to ηp \to 3π^0 p \to 6γp$ events yields the value $α=-0.032\pm0.003$ for the $η\to 3π^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $π^0π^0$ invariant-mass spectrum was investigated for the occurrence of a cusplike structure in the vicinity of the $π^+π^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.
New high-statistics measurement of the $π^0 \to e^+e^-γ$ Dalitz decay at the Mainz Microtron
University of Mainz（美因茨大学）；University of Basel（巴塞尔大学）；University of Bonn（波恩大学）；University of Regina（里贾纳大学）；SUPA School of Physics and Astronomy, University of Glasgow（格拉斯哥大学物理与天文学学院）；Department of Physics, University of York（约克大学物理系）；Joint Institute for Nuclear Research（联合核研究所）；INFN Sezione di Pavia（帕维亚 INFN 分部）；The George Washington University（乔治华盛顿大学）
A new determination of the eta transition form factor in the Dalitz decay eta -> e^+ e^- gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron
