Measurement of the branching fractions and time-dependent CP asymmetry at the Belle II experiment

Ming-Chuan Chang^1*, TzuTing Liu¹, ChaoChun Chang¹, SengZheng Wu¹, ChiHan Tseng¹, EnChi Chang¹, ShengHong He¹, QiJun Wei¹, Mingji Chen¹, TsaiHua Lee¹

¹Physics, Fu Jen Catholic University, New Taipei, Taiwan

* Presenter:Ming-Chuan Chang, email:068190@mail.fju.edu.tw

The branching fractions of B⁰→X_c1 η, B⁰→X_c1 π⁰, B⁰→J/ψ K_L, B⁰_(s)→J/ψ η^('), B⁰_(s)→J/ψ π⁰ are measured. The time-dependent CP asymmetry of B⁰→J/ψ η and B⁰→J/ψ π⁰ are also measured. The data are collected by the Belle and Belle II experiment running at the Υ(4S) resonance at the KEKB and SuperKEKB, the asymmetric energy e⁺ and e^- colliders. The CP asymmetry parameters S and A are performed by an unbinned maximum likelihood fit to the ∆t distribution. The event selections, signal and background PDF modelings, three kinds of B vertex constraints, and flavor tags are reported.

Keywords: branching fraction, time-dependent CP asymmetry, Belle and Belle II experiment