Vismaya V S ; S. Sandilya ; K. Trabelsi

12 July 2023

Abstract: Recent measurements of semileptonic decays show a difference between the branching ratio of the sum of exclusive decay rates and the inclusive $b \rightarrow c \ell \nu$ decay rate (the so-called Semi-Leptonic (SL) gap) which affects the interpretation of the CKM element $|Vcb|$. Large contributions from not-yet measured $B \rightarrow D^* \eta \ell \nu$ decays could explain such difference. We present a study of the $B \rightarrow D^* \eta \pi$ decay on the simulated data sample of the Belle II experiment. This measurement will provide valuable information to predict its semileptonic counterpart $B \rightarrow D^* \eta \ell \nu$. If $B \rightarrow D^* \eta \pi$ decay is found to be large, it could contribute significantly to the hadronic B-tagging, and consequently enhance the sensitivity for searching rare B decays with missing energy.