Measurement of $CP$ violation in $B^0\to D^{+}{D}^{-}$ and $B_s^0\to D_s^{+}{D}_s^{-}$ decays

Abstract

A time-dependent, flavour-tagged measurement of $CP$ violation is performed with $B^0\to D^{+}{D}^{-}$ and $B_s^0\to D_s^{+}{D}_s^{-}$ decays, using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 6 fb${}^{-1}$. In $B^0\to D^{+}{D}^{-}$ decays the $CP$-violation parameters are measured to be \begin{align} S_{D^{+}D^{-}} & = -0.552 \pm 0.100\,\text{(stat)} \pm 0.010\,\text{(syst)}, \nonumber \newline C_{D^{+}D^{-}} & = \phantom{-}0.128 \pm0.103\,\text{(stat)} \pm 0.010\,\text{(syst)}. \nonumber \end{align} In $B_s^0\to D_s^{+}{D}_s^{-}$ decays the $CP$-violating parameter formulation in terms of ${\varphi }_s$ and $|\lambda |$ results in \begin{align} ϕ_{s} & = -0.086 \pm 0.106 \,\text{(stat)} \pm 0.028\,\text{(syst)} \,\text{rad}, \nonumber \newline |λ_{D^{+}_{s}D^{-}_{s}}| & = \phantom{-}1.145 \pm 0.126\,\text{(stat)} \pm 0.031\,\text{(syst)}. \nonumber \end{align} These results represent the most precise single measurement of the $CP$-violation parameters in their respective channels. For the first time in a single measurement, $CP$ symmetry is observed to be violated in $B^0\to D^{+}{D}^{-}$ decays with a significance exceeding six standard deviations.

arXiv commentAll figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/3262/ (LHCb public pages)

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Cited by in corpus (1)

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