First measurement of the decay-time-integrated $CP$ asymmetry in $B_s^0\to D_s^{-}{\pi }^{+}$ decays

Abstract

A measurement of the flavor-untagged decay-time-integrated $CP$ asymmetry in the flavor-specific decay $B_s^0\to D_s^{-}{\pi }^{+}$, $⟨A_{\mathrm{untagged}}^s⟩$, is performed using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of $13\mathrm{TeV}$, corresponding to a total integrated luminosity of $5.4{\mathrm{fb}}^{-1}$. The $CP$ asymmetry is measured in two $D_s^{-}$ meson decay modes, $D_s^{-}\to K^{-}{K}^{+}{\pi }^{-}$ and $D_s^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}$. The combined result, $⟨A_{\mathrm{untagged}}^s⟩=(-1.4\pm 5.9(\mathrm{stat})\pm 1.1(\mathrm{syst}))\times 10^{-3}$, is consistent with the Standard Model expectation and provides a direct constraint on new physics in tree-level $b$-hadron decays.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcb-glance.cern.ch/alcm/public/analysis/full-details/4515 (LHCb public pages)