Effective lifetime measurements in the $B_s^0\to K^{+}{K}^{-}$, $B^0\to K^{+}\ddot{I}{€}^{-}$ and $B_s^0\to \ddot{I}{€}^{+}{K}^{-}$ decays

Abstract

Measurements of the effective lifetimes in the $B_s^0\to K^{+}{K}^{-}$, $B^0\to K^{+}\ddot{I}{€}^{-}$ and $B_s^0\to \ddot{I}{€}^{+}{K}^{-}$ decays are presented using $1.0\mathrm{f}{\mathrm{b}}^{-1}$ of $pp$ collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. The measured effective lifetimes are $\ddot{I}{„}_{B_s^0\to K^{+}{K}^{-}}$ = $1.407\pm 0.016\pm 0.007\mathrm{ps}$, $\ddot{I}{„}_{B^0\to K^{+}\ddot{I}{€}^{-}}$ = $1.524\pm 0.011\pm 0.004\mathrm{ps}$, $\ddot{I}{„}_{B_s^0\to \ddot{I}{€}^{+}{K}^{-}}$ = $1.60\pm 0.06\pm 0.01\mathrm{ps}$. This is the most precise determination to date of the effective lifetime in the $B_s^0\to K^{+}{K}^{-}$ decay and provides constraints on contributions from physics beyond the Standard Model to the $B_s^0$ mixing phase and the width difference $\hat{I}”\hat{I}{“}_s$.

12 pages, 2 Figures