D0-D̄0 mixing sensitivity estimation at Belle II in wrong-sign decays D0 → K+π−π0 via time-dependent amplitude analysis**Supported by National Natural Science Foundation of China (11475164, 11475169, 11675166)

Abstract

The sensitivity of the D0-D̄0 mixing parameters x and y is estimated in the wrong-sign decay D0 → K+π−π0 by time-dependent amplitude analysis. The resolution of the D0 lifetime is essential in time-dependent Dalitz analyses. The Belle II detector, which aims to collect a total integrated luminosity of 50 ab−1 of data, has σ = 140 fs in Monte Carlo studies, a factor of two improvement over that of Belle and BaBar, so the produced Dalitz signal Monte Carlo samples are smeared with this resolution. Then a time-dependent Dalitz plot fitting is performed on these smeared samples, and the sensitivity of D0-D̄0 mixing parameters are σx = 0.057% and σy = 0.049%. These are about an order of magnitude improvement on current experimental results, without considering background effects.