Measurement of $B/s$ lifetime, decay width difference and polarization amplitude of the $B/s\to J/\Psi \phi$ decays at CDF II
In this thesis the update of the measurement of the B$^{0}_{s}$ lifetime, the decay width difference between its heavy and light mass eigenstates and the polarization amplitudes of B$^{0}_{s}$ $\rightarrow$ J/$\psi\phi$ decays of the $^{0}_{s}$ meson is presented. About 9600 B$^{0}_{s}$ → J/ψφ decays have been reconstructed in the final state [$\mu^{+}$ $\mu^{−}$ ][K$^{+}$K$^{-}$ ] using a dataset of p ̄$\overline{p}$ collisions at $\sqrt{s}$ = 1.96 TeV corresponding to 8.4 fb$^{-1}$ integrated luminosity collected by the CDFII detector at the Fermilab Tevatron collider. The results are extracted from an analysis of the angular distributions of muons and kaons as a function of the decay time through an unbinned maximum likelihood fit which exploits identification of the quark content (b or $\overline{b}$ of the strange bottom meson at the time of production. Assuming the Standard Model prediction for the size of CP violation occurring in the B$^{0}_ {s}$ mixing, the estimated lifetime, decay width difference, polarization amplitudes and strong phase of the perpendicular amplitude are: τ (B$^{0}_{s}$) = 1.527 $\pm$ 0.021(stat.)ps, $\Delta\Gamma$ = 0.063 $\pm$ 0.029(stat.)ps$^{-1}$, $\mid$A$_{parallel}$ (0)$\mid^{2}$ = 0.233 $\pm$ 0.014(stat.), $\mid$A$_[0}$ $\mid^{2}$ = 0.514 $\pm$ 0.012(stat.), $\delta_{perpendicular}$ = 2.95 $\pm$ 0.61(stat.)