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

Abstract

A measurement of the flavour-untagged decay-time-integrated $CP$ asymmetry in the flavour-specific decay $B_s^0\to D_s^{-}\ddot{I}{€}^{+}$, $⟨A_{\mathrm{untagged}}^s⟩$, 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, $D_s^{-}\to K^{-}{K}^{+}\ddot{I}{€}^{-}$ and $D_s^{-}\to \ddot{I}{€}^{-}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$. 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://lbfence.cern.ch/alcm/public/analysis/full-details/4515/ (LHCb public pages)