%% Title %\titlepage[\vspace{5mm}Department of Physics,\\ %Graduate School of Science]% %{A dissertation submitted to the Osaka University\\ %for the degree of Doctor of Philosophy} \titlepage[]{\vspace{5mm}Department of Physics, Graduate School of Science\\ Osaka University} %% Abstract \begin{abstract} %[\smaller \thetitle\\ \vspace*{1cm} \smaller {\theauthor}] \thispagestyle{empty} COMET [1] is an experiment that aims to search for a charged lepton flavor violation (CLFV) process, the muon-to-electron conversion in the presence of a nucleus, \muec. The process is forbidden in the Standard Model (SM), however is predicted to occur in various extensions of SM, such as . Current experimental upper limit of the branching ratio is $BR(\mu^{-} + Au \rightarrow e^{-} + Au) < 7 \times 10^{-13}$, set by the SINDRUM II experiment [2]. Using the J-PARC proton beam and the pion capture by a solenoidal field, COMET will have a single event sensitivity 10,000 times better than the current limit. The COMET collaboration has taken a phased approach in which the first phase, COMET Phase-I [3], starts in 2013 and initial data taking in around 2017. In order to optimize detector design for the Phase-I, backgrounds from nuclear muon capture are crucial. We have proposed a dedicated experiment , namely AlCap, at PSI, Switzerland to study the backgrounds, including: heavy charged particles, neutrons and photons. The measurements of heavy charged particles have been carried out in the 2013 run and the preliminary analysis results are presented in this thesis. \end{abstract} %% Declaration \begin{declaration} \thispagestyle{empty} This dissertation is the result of my own work, except where explicit reference is made to the work of others, and has not been submitted for another qualification to this or any other university. \vspace*{1cm} \begin{flushright} Nam Hoai Tran \end{flushright} \end{declaration} % Acknowledgements %\begin{acknowledgements} %\thispagestyle{empty} %Of the many people who deserve thanks, some are particularly prominent, %such as my supervisor Professor Yoshitaka Kuno. %\end{acknowledgements} %% Preface %\begin{preface} %\thispagestyle{empty} %The thesis is about measurements of products of nuclear muon capture on an %aluminum target, which is important for optimization of a tracking detector %of a search for muon to electron conversion, the E21 experiment - so called %COMET - at Japan Proton Accelerator Complex (J-PARC). %\end{preface} %% ToC \tableofcontents %% Strictly optional! %\frontquote{% %Writing in English is the most ingenious torture\\ %ever devised for sins committed in previous lives.}% %{James Joyce}