Measurement of the effective B0s → K+K- lifetime

Abstract

A precise determination of the effectiveB0s→K+K−lifetime can be used to con-strain contributions from physics beyond the Standard Model in theB0smesonsystem. Conventional approaches selectBmeson decay products that are signifi-cantly displaced from theBmeson production vertex. As a consequence,Bmesonswith low decay times are suppressed, introducing a bias to the decay time spectrumwhich must be corrected. This analysis uses a technique that explicitly avoids alifetime bias by using a neural network based trigger and event selection. Using1.0 fb−1of data recorded by the LHCb experiment, the effectiveB0s→K+K−lifetime is measured as 1.455±0.046 (stat.)±0.006 (syst.) ps.