Skip to content

Commit

Permalink
Final version (without Acknowledgments)
Browse files Browse the repository at this point in the history
  • Loading branch information
romainschotter committed Jul 28, 2023
1 parent 711829b commit 73e2e5d
Show file tree
Hide file tree
Showing 132 changed files with 16,876 additions and 814 deletions.
182 changes: 91 additions & 91 deletions ALICEExperiment.tex

Large diffs are not rendered by default.

12 changes: 12 additions & 0 deletions Abstract.tex
Original file line number Diff line number Diff line change
@@ -1,5 +1,17 @@
\chapter*{Abstract}

Quantum Chromodynamics (QCD), the quantum field theory of the strong force, predicts tje existence of an extreme state of nuclear matter in which partons (quarks and gluons) are deconfined and thermalised: this is the so-called \textit{Quark Gluon Plasma} (QGP). Corresponding supposedly to the primordial state of the Universe up to a few micro-seconds after the Big-Bang, the QGP has been studied experimentally at colliders such as the \textit{Large Hadron Collider} (LHC) at CERN in Geneva, during the LHC Run-1 (2009-2013) and Run-2 (2015-2018) data taking periods.

The 5$^{\rm th}$ of July 2022. Nearly four years after the end of the LHC Run-2, the LHC has restarted for a third data taking campaign (LHC Run-3), as well as the experiments installed on the ring: ATLAS, CMS, LHCb, -- and the one in which this thesis is carried out -- ALICE (\textit{A Large Ion Collider Experiment}). Dedicated to the study of QCD and QGP, ALICE has been fully revamped and upgraded in order to i) increase the data taking rates and ii) perform more precise measurements. The objective is clear: with the LHC Run-3, ALICE enters into a new age, an era of precision. In that regard, considering the accumulated statistics throughout the LHC Run-2 (about two billions proton-proton collisions at a centre-of-mass energy of 13 \tev), there already exists plenty of precise measurements, especially in the hyperon sector (baryons containing at least one strange quark).

This thesis proposes to analyse -- possibly, one last time -- the data recorded during the LHC Run-2 before moving on to the ones from the LHC Run-3, in order to fully exploit them and push them to their precision limits. To that end, two analyses have been performed.

The first analysis consists in a test of the CPT (Charge-Parity-Time) symmetry via the mass difference measurement of multi-strange baryons (\rmXiM[$dss$] and \rmAxiP[$\bar{d}\bar{s}\bar{s}$], and \rmOmegaM[$sss$] and \rmAomegaP[$\bar{s}\bar{s}\bar{s}$]). The current mass and mass difference values given by the \textit{Particle Data Group} (PDG) for these two baryons relying on measurements with relatively low statistics, it becomes now possible to improve them in order to test the CPT symmetry to an unprecedented level of precision, thanks to the abundant production and detection of these baryons by ALICE at the LHC. The total uncertainty on the mass values has been reduced by a factor 1.19 for the \rmXiM and \rmAxiP, and 9.26 for the \rmOmegaM et \rmAomegaP. Concerning the mass differences, their precision has been improved by 20\% for the \rmXi, and by more than a factor two for the \rmOmega.

The second analysis aims to provide a better understanding of the production mechanisms of strange quarks in proton-proton collisions at \sqrtS = 13 \tev. This is achieved by studying the correlations between identified particles. In practice, this analysis focuses specifically on correlations between a multi-strange baryon --- \rmXiPM or \rmOmegaPM\ --- and a \rmPhiMes resonance. The first results show that the production of \rmPhiMes increases in the vicinity (in azimuth) of a \rmXiPM. No correlation with the rapidity separation has been observed yet. Furthermore, the available statistics remains too low to study the \rmOmega\ --\ \rmPhiMes correlation.\\

\noindent\textbf{Key words:} particle physics, heavy-ion physics, ALICE, LHC, CERN, CPT symmetry, correlated production, multi-strange baryons, strange hadrons, strangeness, precision measurement, mass measurement, mass difference measurement.




Expand Down
8 changes: 4 additions & 4 deletions AppendixCPTAnalysis.tex
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ \chapter{Complementary materials for the analysis:\\Mass measurements of multi-s

\section{Study of the systematic effects: topological and track selections}

\subsubsection{Topological and track selections}
%\subsection{Topological and track selections}

\begin{table}[h]
\centering
Expand Down Expand Up @@ -143,7 +143,7 @@ \section{Summary of the systematic uncertainties}
\bf Total &\bf 0.022 &\bf 0.256\\
\noalign{\smallskip}\hline \noalign{\smallskip}
\end{tabular}
\caption{Statistical and systematical uncertainties on the mass \rmKzeroS. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassK0s}
\caption{Statistical and systematic uncertainties on the mass \rmKzeroS. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassK0s}
\end{table}

\begin{table}[H]
Expand All @@ -168,7 +168,7 @@ \section{Summary of the systematic uncertainties}
\bf Total &\bf 0.011 &\bf 0.066 &\bf 0.011 &\bf 0.065 \\
\noalign{\smallskip}\hline \noalign{\smallskip}
\end{tabular}
\caption{Statistical and systematical uncertainties on the mass \rmLambda and \rmAlambda. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassLambda}
\caption{Statistical and systematic uncertainties on the mass \rmLambda and \rmAlambda. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassLambda}
\end{table}

\begin{table}[H]
Expand All @@ -193,6 +193,6 @@ \section{Summary of the systematic uncertainties}
\bf Total &\bf 1.34 & \bf 2.27 \\
\noalign{\smallskip}\hline \noalign{\smallskip}
\end{tabular}
\caption{Statistical and systematical uncertainties on the mass \rmLambda and \rmAlambda. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassDiffLambda}
\caption{Statistical and systematic uncertainties on the mass \rmLambda and \rmAlambda. The total is obtained assuming that there is no correlation between each source of uncertainties.}\label{tab:SystMassDiffLambda}
\end{table}

Loading

0 comments on commit 73e2e5d

Please sign in to comment.