Search for CPT and Lorentz violation in B0 mixing with B0 -> J/psi KS at LHCb

Abstract

Effects of CPT and Lorentz violation in neutral meson mixing, in particular the sensitivity of the LHCb detector, have been studied. To parametrize CPT and Lorentz violation, the Standard Model Extension has been used. At LHCb, B0 mixing in B0 -> J/psi KS has the highest sensetivity to Standard Model Extension parameter ∆aμ (B0). Using a decay-time dependent analysis and the periodogram method, B0 mixing has been measured to be consistent with no CPT and no Lorentz violation. The likelihood fit, without systematic uncertainties, resulted in ∆a0 − 0.38∆aZ = (−0.8 ± 1.1 (stat.)) × 10^-15 GeV, ∆aX = (−0.7 ± 1.7 (stat.)) × 10^-15 GeV, ∆aY = (+0.6 ± 1.6 (stat.)) × 10^-15 GeV, making this the world’s best measurement of ∆aμ (B0) to date.