Search for CP Violation in D~0→K~O_sK~O_s Decay at Belle and Belle II

摘要

165.1 Introduction Charge-conjugation Parity Violation (CPV) in charmed meson decays has not yet been observed and is predicted to be (10~(-3)) in the Standard Model (SM). An evidence for CPV in 2012 by LHCb (-0.82 ± 0.21 ± 0.11)% [1] suggested a 3.5 standard deviation (a), confirmed by CDF [2], took people by surprise and revived the field. Measurements of {formula} have been performed by LHCb, CDF, BaBar and Belle collaborations [3, 4]. Recently LHCb updated ΔA_(CP) result with a larger data sample and there is no evidence of non-zero asymmetry [4]. The combined result of ΔA_(CP) by HFAG [5] gives an agreement with no CPV at 9.3% confidence level (CL). Though there is no current evidence of non-zero asymmetry, CPV in charm decays is investigated in other channels. Singly Cabibbo-suppressed (SCS) decays are of special interest as the possibility of interference with NP amplitudes could lead to larger CPV than predicted by SM, The D~0→K0sK0s decay is one such channel [6].