Boyang Zhang is a Belle II experimentalist from Hawaii.

Talk Title: Sensitivity to R(D)(*) with inclusive tagging at Belle II

Measurements of \( R(D) \) and \( R(D^*) \) serve as probes for lepton flavor universality (LFU), a principle assumed in the Standard Model (SM). These ratios compare the total rates of B meson semileptonic decays involving different lepton flavors, specifically in \( b \rightarrow c l \nu \) transitions. For instance, \( R(D) \) is defined as \( \Gamma[B \rightarrow D \tau \nu] / \Gamma[B \rightarrow D \ell \nu] \), where \( \ell \) represents either \( e \) or \( \mu \). Over the past decade, B-factories such as Babar, Belle/Belle II, and LHCb have been measuring these ratios using various methods. The combined results exhibit a 3 sigma deviation from the SM prediction.

In this talk, I will briefly introduce recent efforts by Belle II in these measurements and then describe a novel method utilizing the inclusive tagging technique. This new approach offers an order of magnitude higher tagging efficiency compared to the most precise measurements to date, though it comes with lower purity and higher background. I will present the sensitivity of the inclusive tagging method and discuss potential systematic uncertainties.