1. Prospects for CP and P violation in Λc+ decays at Super Tau Charm Facility.
- Author
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Xiao-Dong Shi, Xian-Wei Kang, Ikaros Bigi, Wei-Ping Wang, and Hai-Ping Peng
- Subjects
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CP violation , *HADRON decay , *MONTE Carlo method - Abstract
CP violation is an excellent tool for probing flavor dynamics as we learned first with KL→2π and later also with the weak decays of beauty mesons. LHCb 2019 data have shown CP violation for the first time in D0→K-K+ vs D0→π-π+. Searching for CP asymmetries is of great interest in the charm quark sector in the Standard Model (SM) or even more beyond it. In charm hadron decays, lots of work had focused on two-body final states, and the measurements of CP asymmetries in three- or four-body final states are rare. Dalitz plots have shown an excellent record for three-body final states, and more results are desired for four-body ones. In this work we study CP asymmetries in the decays Λc+→pK-π+π0/Λπ+π+π-/pKSπ+π-, where the SM gives zero values for the first two channels, while 3.3×10-3 is given for the last one due to K0-K̅0 oscillation. We performed a fast Monte Carlo simulation study by using electron-positron annihilation data of 1 ab-1 at center-of-mass energy √s=4.64 GeV. The data is expected to be available by the next generation Super Tau Charm Facility proposed by China and Russia with one year (or even less) of the data taking operation. The results indicate that a sensitivity at the level of 0.2~0.5% is accessible for these processes, which would be enough to measure nonzero CP-violating asymmetries as large as 1%. Furthermore AT-odd≠0 can establish parity violation by themselves and likewise for A̅T-odd≠0. The SM is based on W+/- being 100% left handed. One can compare decay asymmetry parameters aP from Λc+→Λe+ν vs a̅P from Λ̅c-→Λ̅e-ν̅. In the SM one gets aP=1 and a̅P=-1 in the SM, while present data give the following: (aP+a̅P)/2=0.00±0.04. Probing these nonleptonic decays of Λc+ would give new lessons about nonperturbative QCD or even indirect impact of new dynamics on parity violation. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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