Slow-Pion Relative Tracking Efficiency Studies at Belle II

Abstract

We study B0→D∗−π+ and B0→D∗−ρ+ decay modes to calculate the slow-pion relative tracking efficiency, where the D∗− further goes to D0¯¯¯¯¯¯ and π−. Owing to its limited phase space, the pion from D∗ decay is traditionally referred to as the slow pion due to a small mass difference between the D∗ and D0¯¯¯¯¯¯. We report herein a measurement of efficiency in the momentum region of 50–320 MeV/c using B0→D∗−π+ and B0→D∗−ρ+ decay modes in simulated data.