Measurement of the effective B0s→K+K− lifetime

Abstract

A precise determination of the effective B0 s → K + K − lifetime can be used to constrain contributions from physics beyond the Standard Model in the B0 s meson system. Conventional approaches select B meson decay products that are significantly displaced from the B meson production vertex. As a consequence, B mesons with low decay times are suppressed, introducing a bias to the decay time spectrum which must be corrected. This analysis uses a technique that explicitly avoids a lifetime bias by using a neural network based trigger and event selection. Using 1.0 fb−1 of data recorded by the LHCb experiment, the effective B0 s → K + K − lifetime is measured as 1.455 ± 0.046 (stat.) ± 0.006 (syst.) ps. © 2012 CERN. Published by Elsevier B.V. All rights reserved.