The two-photon radiative decay process J/ψ→2γ+hadrons was studied,and the main contribution processes,J/ψ→2γ+ggg and J/ψ→2γ+qˉq,were calculated.With the specific conditions at the BESIII,this rare decay proc...The two-photon radiative decay process J/ψ→2γ+hadrons was studied,and the main contribution processes,J/ψ→2γ+ggg and J/ψ→2γ+qˉq,were calculated.With the specific conditions at the BESIII,this rare decay process and the main background process e+e?→γγ+hadrons(qˉq)were investigated.The results show that the ratio of signal to background can reach 1.24 with optimized selection criteria at the BESIII.In addition,distributions of the signal and background are presented.All the results show that the signal is large enough to be experimentally measured.展开更多
We study the decay process of J/ψ→ e＋e-φ where the relatively clean electromagnetic （EM） transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitio...We study the decay process of J/ψ→ e＋e-φ where the relatively clean electromagnetic （EM） transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitions. We include the low-lying scalar f0（980） and pseudoscalar η/η′ as the dominant contributions in the evaluation of the hadronic loop contributions. It is found that the hadronic effects are negligible compared with the EM contributions. The decay width of J/ψ→ e＋e-φis determined to be about 2.12 × 10^-6 keV if there is no other leading mechanism contributing. This result will be tested by the BESIII experiment with a large J/ψ data sample.展开更多
The study of hyperon decays at the Beijing Electron Spectrometer Ⅲ （BESⅢ） is proposed to investigate the events of J/φ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing El...The study of hyperon decays at the Beijing Electron Spectrometer Ⅲ （BESⅢ） is proposed to investigate the events of J/φ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron-Positron Collider Ⅱ. About 10^6-10^8 hyperons, i.e., ∧, ∑, ∈, and Ω, will be produced in the J/φ and φ（2S） decays with the proposed data samples at BESⅢ. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of 10^-5-10^-8. In addition, with the known center-of-mass energy and ＂tag technique＂, rare decays and decays with invisible final states can be probed.展开更多
基金the National Natural Science Foundation of China(12135013)National Key Research and Development Program of China(2020YFA0406400)。
文摘The two-photon radiative decay process J/ψ→2γ+hadrons was studied,and the main contribution processes,J/ψ→2γ+ggg and J/ψ→2γ+qˉq,were calculated.With the specific conditions at the BESIII,this rare decay process and the main background process e+e?→γγ+hadrons(qˉq)were investigated.The results show that the ratio of signal to background can reach 1.24 with optimized selection criteria at the BESIII.In addition,distributions of the signal and background are presented.All the results show that the signal is large enough to be experimentally measured.
基金Supported by National Natural Science Foundation of China(11375128,11425525)Sino-German CRC 110 Symmetries and the Emergence of Structure in QCD(11261130311)
文摘We study the decay process of J/ψ→ e＋e-φ where the relatively clean electromagnetic （EM） transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitions. We include the low-lying scalar f0（980） and pseudoscalar η/η′ as the dominant contributions in the evaluation of the hadronic loop contributions. It is found that the hadronic effects are negligible compared with the EM contributions. The decay width of J/ψ→ e＋e-φis determined to be about 2.12 × 10^-6 keV if there is no other leading mechanism contributing. This result will be tested by the BESIII experiment with a large J/ψ data sample.
基金Acknowledgements The author would like to thank Stephen L. Olsen, I. I. Bigi, and Xu Feng for useful discussions and suggestions and also J. G. K＆rner, Francesco Dettori, and J. Tandean for their useful comments. This work is supported in part by the National Natural Science Foundation of China under Contracts Nos. 11335009 and 11125525, the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contract No. U1532257, CAS under Contract No. QYZDJ-SSW-SLH003, and the National Key Basic Research Program of China under Contract No. 2015CB856700.
文摘The study of hyperon decays at the Beijing Electron Spectrometer Ⅲ （BESⅢ） is proposed to investigate the events of J/φ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron-Positron Collider Ⅱ. About 10^6-10^8 hyperons, i.e., ∧, ∑, ∈, and Ω, will be produced in the J/φ and φ（2S） decays with the proposed data samples at BESⅢ. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of 10^-5-10^-8. In addition, with the known center-of-mass energy and ＂tag technique＂, rare decays and decays with invisible final states can be probed.
