First measurement of time-dependent CP violation in the flavor-changing neutral-current decay B⁰→ K_S⁰μ⁺μ^-

2026/03/13 by LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb +1165 · 1 voice · 1 citation
Physics and Astronomy · #hep-ex

paper · pdf · doi:10.1103/nnt3-nyds

arxiv published 2026/03/13 · arxiv updated 2026/07/05

Abstract

A flavor-tagged time-dependent analysis of B⁰→ K_S⁰μ⁺μ^- decays is performed across the full dimuon mass range excluding the J/ψ and ψ(2S) resonance regions. The analysis uses proton-proton collision data collected by the LHCb experiment in 2011--2018 at center-of-mass energies of 7, 8 and 13TeV, corresponding to an integrated luminosity of 9fb^-1. The CP violation parameters are determined to be C=-0.13 ± 0.32 ± 0.04 and S= +0.82± 0.29 ± 0.05, where the first uncertainties are statistical and the second are systematic. The results are consistent with the Standard Model prediction. This is the first experimental study of time-dependent CP violation in b→ sl⁺l^- processes.

Citations

• The LHCb Stripping Project: Sustainable Legacy Data Processing for High-Energy Physics
• Plan B: New Z^′ models for b→ sl⁺l^- anomalies
• Decay time integrals in neutral meson mixing and their efficient evaluation
• sFit: a method for background subtraction in maximum likelihood fit
• Geant4 developments and applications
• Greedy function approximation: A gradient boosting machine.

Cited by

• C P violation analysis of local and nonlocal amplitudes in the B⁰ → K^*0μ⁺μ^- decay

Discussions

• First measurement of time-dependent CP violation in the decay flavor-changing neutral-current decay B⁰→Kₛ⁰μ⁺μ⁻ arxiv.org/abs/2603.13223 - The CP violation parameters are determined to be C=−0.13±0.32± [bsky, 3 points, 0 comments]

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