Measurement of the effective $B_s^0\to K^{+}{K}^{-}$ lifetime

Abstract

A precise determination of the effective $B_s^0\to K^{+}{K}^{-}$ 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 $B_s^0\to K^{+}{K}^{-}$ lifetime is measured as $1.455\pm 0.046(stat.)\pm 0.006(syst.)\mathrm{ps}.$

10 pages, 2 figures. Published in Physics Letters B, Volume 716, Issues 3 to 5, 2 October 2012, Pages 393 to 400