Speaker
Description
A measurement of the $B_s^0\rightarrow J/\psi\phi$ decay parameters using $80~\mathrm{fb}^{-1}$ of integrated luminosity collected with the ATLAS detector from $13~\mathrm{TeV}$ proton-proton collisions at the LHC is presented. The measured parameters include the $\textit{CP}$-violating phase $\phi_s$, the width difference $\Delta\Gamma_s$ between the $B_s^0$ meson mass eigenstates and the average decay width $\Gamma_s$. The values measured for the physical parameters are combined with those from $19.2~\mathrm{fb}^{-1}$ of $7~\mathrm{TeV}$ and $8~\mathrm{TeV}$ data, leading to the following:
\begin{equation}
\phi_s=-0.087\pm0.036~(\mathrm{stat.})\pm0.021~(\mathrm{syst.})~\mathrm{rad}
\end{equation}
\begin{equation}
\Delta\Gamma_s=0.0657\pm0.0043~(\mathrm{stat.})\pm0.0037~(\mathrm{syst.})~\mathrm{ps}^{-1}
\end{equation}
\begin{equation}
\Gamma_s=0.6703\pm0.0014~(\mathrm{stat.})\pm0.0018~(\mathrm{syst.})~\mathrm{ps}^{-1}
\end{equation}
Results for $\phi_s$ and $\Delta\Gamma_s$ are also presented as $68\%$ confidence level contours in the $\phi_s-\Delta\Gamma_s$ plane. Furthermore, the transversity amplitudes and corresponding strong phases are measured. $\phi_s$ and $\Delta\Gamma_s$ measurements are in agreement with the Standard Model predictions.
| Career stage | Graduate student |
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