First measurement of the $CP$-violating phase in $B_s^0\to J/\psi (\to e^{+}{e}^{-})\varphi$ decays

Abstract

A flavour-tagged time-dependent angular analysis of $B_s^0\to J/\psi \varphi$ decays is presented where the $J/\psi$ meson is reconstructed through its decay to an $e^{+}{e}^{-}$ pair. The analysis uses a sample of $pp$ collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb${}^{-1}$. The $CP$-violating phase and lifetime parameters of the $B_s^0$ system are measured to be ${\varphi }_s=0.00\pm 0.28\pm 0.07$ rad, $\Delta {\Gamma }_s=0.115\pm 0.045\pm 0.011$ ps${}^{-1}$ and ${\Gamma }_s=0.608\pm 0.018\pm 0.012$ ps${}^{-1}$ where the first uncertainty is statistical and the second systematic. This is the first time that $CP$-violating parameters are measured in the $B_s^0\to J/\psi \varphi$ decay with an $e^{+}{e}^{-}$ pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-042.html (LHCb public pages)

References in corpus (11)

• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• sPlot: a statistical tool to unfold data distributions
• Performance of the LHCb RICH detector at the LHC
• Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics
• The Unitarity Triangle Fit in the Standard Model and Hadronic Parameters from Lattice QCD: A Reappraisal after the Measurements of Delta m_s and BR(B to tau nu)
• Precision measurement of $CP$ violation in $B_s^0\to J/\psi K^{+}{K}^{-}$ decays
• S-waves and the Measurement of CP Violating Phases in Bs Decays
• Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
• Observation of the decay $B_c^{+}\to \psi (2S){\pi }^{+}$
• Flavour tagged time dependent angular analysis of the $B_s\to J/\psi \varphi$ decay and extraction of $\Delta \Gamma$ and the weak phase ${\varphi }_s$ in ATLAS
• A new algorithm for identifying the flavour of $B_s^0$ mesons at LHCb