Measurement of the $B_s^0\to J/\psi K_S^0$ branching fraction

TL;DR

This paper reports the most precise measurement to date of the branching fraction for the decay $B_s^0 o J/si K_S^0$, providing insights into penguin contributions affecting CP violation measurements.

Contribution

The paper presents a new, highly precise measurement of the $B_s^0 o J/si K_S^0$ branching fraction using LHCb data, improving upon previous results.

Findings

Measured branching fraction: (1.83 ± 0.28) × 10^{-5}

Provides the most precise value to date

Offers insights into penguin contributions in CP violation

Abstract

The $B_s^0\to J/\psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$\beta$ measurement from $B^0\to J/\psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}$. This is the most precise measurement to date.