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تسجيل مستخدم جديدMeasurement of the effective B_s^0 -> J/{psi} K_S^0 lifetime
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This paper reports the first measurement of the effective B_s^0 -> J/{psi} K_S^0 lifetime and an updated measurement of its time-integrated branching fraction. Both measurements are performed with a data sample, corresponding to an integrated luminosity of 1.0 fb^{-1} of pp collisions, recorded by the LHCb experiment in 2011 at a centre-of-mass energy of 7 TeV. The results are: tau_J/{psi}K_S^0 = 1.75 +/- 0.12 (stat) +/- 0.07 (syst) and BR(B_s^0 -> J/{psi} K_S^0) = (1.97 +/- 0.23) X 10^{-5}. For the latter measurement, the uncertainty includes both statistical and systematic sources.
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The $B_s^0to J/psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$b
eta$ measurement from $B^0to J/psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0to J/psi K_S^0)=(1.83pm0.28)times10^{-5}$. This is the most precise measurement to date.
A measurement of the branching fraction of the decay $B_s^0 to K_S^0 K_S^0$ is performed using proton-proton collision data corresponding to an integrated luminosity of 5 $fb^{-1}$ collected by the LHCb experiment between 2011 and 2016. The branching
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A precise determination of the effective $B_s^0 rightarrow K^+ K^-$ 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 s
ignificantly 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 $B_s^0 rightarrow K^+ K^-$ lifetime is measured as $1.455 pm 0.046 ; mathrm{(stat.)} pm 0.006 ; mathrm{(syst.)} , mathrm{ps}.$
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trm{eff}}$, is measured to be $tau_{textrm{eff}} = 1.479 pm 0.034~textrm{(stat)} pm 0.011 ~textrm{(syst)}$ ps. Assuming $CP$ conservation, $tau_{textrm{eff}}$ corresponds to the lifetime of the light $B_s^0$ mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.
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