2016/08/31 by R. Baldini Ferroli, F. De Mori, M. Destefanis +25 · 1 citation
Mathematics · Physics and Astronomy · #Algorithm #Black Holes and Theoretical Physics #Mathematics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.95.034038
published in Physical review. D/Physical review. D. 95(3) (American Physical Society) · 12 pages, 7 figures
arxiv created 2016/09/09 · openalex created_date 2016/09/16 · openalex publication_date 2017/02/27 · arxiv updated 2017/03/08 · openalex updated_date 2026/08/05
The J/\ensuremathψ meson has negative G parity so that, in the limit of isospin conservation, its decay into \ensuremathπ+\ensuremathπ^\ensuremath- should be purely electromagnetic. However, the measured branching fraction B(J/\ensuremathψ\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath-) exceeds by more than 4.5 standard deviations the expectation computed according to BABAR data on the e+e^\ensuremath-\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath- 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^\ensuremath-\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath- cross section in the J/\ensuremathψ mass energy region, can definitely prove or disprove this strong G-parity-violating mechanism by confirming or confuting the BABAR data.