28 July 2020 to 6 August 2020
virtual conference
Europe/Prague timezone

Radiative and Rare Charm Decays at BESIII

28 Jul 2020, 17:00
15m
virtual conference

virtual conference

Talk 05. Quark and Lepton Flavour Physics Quark and Lepton Flavour Physics

Speaker

Dr Bo Zheng (University of South China)

Description

In this talk, we present the latest result on radiative and rare/forbidden decays for D mesons at the BESIII experiment based on 2.92 fb-1 and 3.19 fb-1 data taken at the center-of-mass energy 3.773 4.178 GeV with the BESIII detector, respectively. Based the data at 4.178 GeV, a search for the rare radiative leptonic decay Ds->gamma e+ nu is performed for the first time with negative result and an upper limit (UL) of the branching fraction(BF) is set to be less than 1.310E-4 at 90\% confidence level (CL). With this data sample, we also search for the rare decay Ds-> p bar e+ nu. No significant signal is observed, and an UL B(Ds -> p pbar e+ nu)<2.010E-4 is determined at the 90\% CL. Using the dataset at 3.773 GeV, we search for rare decays of D-> h(h’)e+e- with double tag method, where h(‘) are hadrons. No significant excess over the expected backgrounds is observed, the ULs on the signal BFs at the 90\% CL are determined. For the D+ decays, the searches are performed for the first time, while for D0 decays, the ULs are improved in general by a factor of 10, compared to previous measurements. All the ULs on the BF, at the level of $10E-5~10E-6, are above the SM predictions, which include both LD and SD contributions. Also, we search for the Majorana neutrino in the lepton number violating (LNV) decays $D\to K pi e+e-. No significant signal is observed, and the ULs on the BF at the 90\% CL are set to be less than few $10E-6. The Majorana neutrino is searched for with different mass assumptions ranging from 0.25 to 1.0 GeV/ in the decays D0 -> K- e+ nu_N(pi- e+) and D+->KS e+ nu_N(pi-e+), and the UL on the BF at the 90\% CL are extracted to be at the level of $10E-7~10E-6. The constraints on the mixing matrix element |V_{eN}|^2 are also evaluated.

Primary author

Dr Bo Zheng (University of South China)

Presentation Materials