Measurement of the effective B-s(0) -> K+ K- lifetime

A precise determination of the effective B-s(0) -> K+ K- lifetime can be used to constrain contributions from physics beyond the Standard Model in the B-s(0) 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 B-s(0) -> K+ K- lifetime is measured as 1.455 +/- 0.046 (stat.) +/- 0.006 (syst.) ps. (c) 2012 CERN. Published by Elsevier B.V. All rights reserved.