Triggering on CP Violation Real-Time Selection and Reconstruction of $\text{B}_{\text{s}}\to\text{J}\mskip -1mu/\mskip -1mu \text{ψ} \mskip 2mu\text{φ}$ Decays

This thesis describes the analysis of the sample of $\text{B}_{\text{s}}\to\text{J}\mskip -1mu/\mskip -1mu \text{ψ} \mskip 2mu\text{φ}$ decays obtained from $pp$ collision data, corresponding to a luminosity of 3 $\text{fb}^{-1}$, collected with the LHCb detector in 2011 and 2012. The main goal of the analysis is the measurement of the $C\mskip -2mu P$-violating weak mixing phase $\phi_{\text{s}}$ and the decay width difference, ${\Delta\Gamma}_{\text{s}}$, between the mass eigenstates of the $\text{B}_{\text{s}}$-$\overline{\text{B}}_{\text{s}}$ system. The aspects of the analysis that are described in most detail are the real-time reconstruction and selection of the events, the determination of the dependency of the selection efficiency on the $\text{B}_{\text{s}}$ decay-time, and the calibration of the decay-time resolution model. The result of a maximum-likelihood fit to the data is: $\phi_s = \text{-}0.057 \pm 0.051 \pm 0.007$ rad, and $\Delta\Gamma_{\text{s}} = 0.0785 \pm 0.0092 \pm 0.0027$ $\text{ps}^{-1}$, where the first uncertainty is statistical and the second is systematic. These results for are compatible with no $C\mskip -2mu P$-violation in $\text{B}_{\text{s}}\to\text{J}\mskip -1mu/\mskip -1mu \text{ψ} \mskip 2mu\text{φ}$ decays and with their Standard Model predictions.