The J/ψ meson has negative G parity so that, in the limit of isospin conservation, its decay into π+π- should be purely electromagnetic. However, the measured branching fraction B(J/ψ→π+π-) exceeds by more than 4.5 standard deviations the expectation computed according to BABAR data on the e+e-→π+π- cross section. The possibility that the two-gluon plus one-photon decay mechanism is not suppressed by G-parity conservation is discussed, even by considering other multipion decay channels. As also obtained by phenomenological computation, such a decay mechanism could be responsible for the observed discrepancy. Finally, we notice that the BESIII experiment, having the potential to perform an accurate measurement of the e+e-→π+π- cross section in the J/ψ mass energy region, can definitely prove or disprove this strong G-parity-violating mechanism by confirming or confuting the BABAR data.
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Data di pubblicazione: | 2017 | |
Titolo: | New G-parity violating amplitude in the J/Psi decay? | |
Autori: | Baldini Ferroli, R.; De Mori, F.; Destefanis, M.; Maggiora, M.; Pacetti, S.; Yan, L.; Bertani, M.; Calcaterra, A.; Felici, G.; Patteri, P.; Wang, Y. D.; Zallo, A.; Bettoni, D.; Cibinetto, G.; Farinelli, Riccardo; Fioravanti, E.; Garzia, Isabella; Mezzadri, Giulio; Santoro, V.; Savriã©, M.; Bianchi, F.; Greco, M.; Marcello, S.; Spataro, S.; Carloni Calame, C. M.; Montagna, G.; Nicrosini, O.; Piccinini, F. | |
Rivista: | PHYSICAL REVIEW D | |
Parole Chiave: | Physics and Astronomy (miscellaneous) | |
Abstract in inglese: | The J/ψ meson has negative G parity so that, in the limit of isospin conservation, its decay into π+π- should be purely electromagnetic. However, the measured branching fraction B(J/ψ→π+π-) exceeds by more than 4.5 standard deviations the expectation computed according to BABAR data on the e+e-→π+π- cross section. The possibility that the two-gluon plus one-photon decay mechanism is not suppressed by G-parity conservation is discussed, even by considering other multipion decay channels. As also obtained by phenomenological computation, such a decay mechanism could be responsible for the observed discrepancy. Finally, we notice that the BESIII experiment, having the potential to perform an accurate measurement of the e+e-→π+π- cross section in the J/ψ mass energy region, can definitely prove or disprove this strong G-parity-violating mechanism by confirming or confuting the BABAR data. | |
Digital Object Identifier (DOI): | 10.1103/PhysRevD.95.034038 | |
Handle: | http://hdl.handle.net/11392/2378228 | |
Appare nelle tipologie: | 03.1 Articolo su rivista |