101 lines
4.1 KiB
TeX
101 lines
4.1 KiB
TeX
%% Title
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%\titlepage[\vspace{5mm}Department of Physics,\\
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%Graduate School of Science]%
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%{A dissertation submitted to the Osaka University\\
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%for the degree of Doctor of Philosophy}
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\titlepage[]{\vspace{5mm}Department of Physics, Graduate School of Science\\
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Osaka University}
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%% Abstract
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\begin{abstract}
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%[\smaller \thetitle\\ \vspace*{1cm} \smaller {\theauthor}]
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\thispagestyle{empty}
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COMET [1] is an experiment that aims to search for a charged lepton flavour
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violation (CLFV) process, the muon-to-electron conversion in the presence of
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a nucleus,
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\muec. The process is forbidden in the Standard Model (SM), however is
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predicted to occur in various extensions of SM. Current experimental
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upper limit of the branching ratio is $BR(\mu^{-} + Au \rightarrow e^{-} + Au)
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< 7 \times 10^{-13}$, set by the SINDRUM II experiment [2].
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Using the J-PARC proton beam and the pion capture by
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a solenoidal field, COMET will have a single event sensitivity 10,000 times
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better than the current limit. The COMET collaboration has taken a phased
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approach in which the first phase, COMET Phase-I [3], starts in 2013 and
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initial data taking in around 2017.
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In order to optimize detector design for the Phase-I, backgrounds from nuclear
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muon capture are crucial. We have proposed a dedicated experiment, namely
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AlCap, at PSI, Switzerland to study the backgrounds, including protons,
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neutrons and photons. The measurements of proton rate and spectrum on
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aluminium have been carried out in the 2013 run. The second run to study
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neutrons and photons is planned in 2015.
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The preliminary results from the analysis of the 2013 run are presented in this
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thesis. The measured proton spectrum peaks at \SI{3.7}{\MeV} and decays
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exponentially with the decay constant of \SI{2.6}{\MeV}. The emission
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rate of protons in the energy range from \SIrange{4}{8}{\MeV} is
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$(1.7\pm0.1)\%$. The total proton emission rate is estimated to be
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$(3.5\pm0.2)\%$ assuming the spectrum shape holds.
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The resulted proton rate and spectrum were used to optimise the tracking
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detector hit rate of the COMET Phase-I.
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\end{abstract}
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%% Declaration
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\begin{declaration}
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\thispagestyle{empty}
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This dissertation is the result of my own work, except where explicit
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reference is made to the work of others, and has not been submitted
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for another qualification to this or any other university.
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\vspace*{1cm}
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\begin{flushright}
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Nam Hoai Tran
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\end{flushright}
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\end{declaration}
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% Acknowledgements
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\begin{acknowledgements}
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\thispagestyle{empty}
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First and foremost I would like to thank my supervisor Yoshitaka
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Kuno, for his great support and almost infinite patience in last four years.
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I am also grateful to all members of the Kuno group, Department of
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Physics, Osaka University. Thanks to Akira Sato, Hideyuki Sakamoto for the
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knowledge and supervision they have provided. And to Takahisa Itahashi
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for the advice and allowing me to practice on his expensive silicon detectors.
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The measurement described in this thesis is the product of effort of all
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members of the AlCap Collaboration. Special thanks to Peter Kammel for
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always pushing the experiment forward and your very helpful advices.
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I enjoyed the stays at your group at University of Washington in Seattle
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a lot. I would also like to thank the
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fellow graduate students in the collaboration Andy, John, Ben, Damien for
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all the hard work in the beam time, in the analysis phase, and also for
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the beers. I wish you all success with your work.
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Finally, I would like to thank my family and friends. Without your love and
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support I wouldn't make it through these long years of graduate school.
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\end{acknowledgements}
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%% Preface
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%\begin{preface}
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%\thispagestyle{empty}
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%The thesis is about measurements of products of nuclear muon capture on an
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%aluminium target, which is important for optimization of a tracking detector
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%of a search for muon to electron conversion, the E21 experiment - so called
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%COMET - at Japan Proton Accelerator Complex (J-PARC).
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%\end{preface}
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%% ToC
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\tableofcontents
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%% Strictly optional!
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%\frontquote{%
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%Writing in English is the most ingenious torture\\
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%ever devised for sins committed in previous lives.}%
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%{James Joyce}
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