Precision Measurement of $CP$ Violation in the Penguin-Mediated Decay ${B}_{s}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}\ensuremath{\phi}$

Open Access

Precision Measurement of $C P$ Violation in the Penguin-Mediated Decay $B_{s}^{0} \to ϕ ϕ$

R. Aaij et al. (LHCb Collaboration)

Phys. Rev. Lett. 131, 171802 – Published 23 October 2023

Abstract

A flavor-tagged time-dependent angular analysis of the decay $B_{s}^{0} \to ϕ ϕ$ is performed using $p p$ collision data collected by the LHCb experiment at the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $6 {fb}^{- 1}$ . The $C P$ -violating phase and direct $C P$ -violation parameter are measured to be $ϕ_{s}^{s \bar{s} s} = - 0.042 \pm 0.075 \pm 0.009 rad$ and $| λ | = 1.004 \pm 0.030 \pm 0.009$ , respectively, assuming the same values for all polarization states of the $ϕ ϕ$ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using $p p$ collisions at center-of-mass energies of 7 and 8 TeV, yielding $ϕ_{s}^{s \bar{s} s} = - 0.074 \pm 0.069 rad$ and $| λ | = 1.009 \pm 0.030$ . This is the most precise study of time-dependent $C P$ violation in a penguin-dominated $B$ meson decay. The results are consistent with $C P$ symmetry and with the standard model predictions.

Received 20 April 2023
Revised 28 June 2023
Accepted 1 August 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.171802

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