COMET Phase-I technical design report
Authors:   The COMET Collaboration, Abramishvili R , Adamov G , Akhmetshin R R , Allin A , Angélique J C , Anishchik V , Aoki M , Aznabayev D , Bagaturia I , Ban G , Ban Y , Bauer D , Baygarashev D , Bondar A E , Cârloganu C , Carniol B , Chau T T , Chen J K , Chen S J , Cheung Y E , da Silva W , Dauncey P D , Densham C , Devidze G , Dornan P , Drutskoy A , Duginov V , Eguchi Y , Epshteyn L B , Evtoukhovitch P , Fayer S , Fedotovich G V , Finger Jr M , Finger M , Fujii Y , Fukao Y , Gabriel J L , Gay P , Gillies E , Grigoriev D N , Gritsay K , Hai V H , Hamada E , Hashim I H , Hashimoto S , Hayashi O , Hayashi T , Hiasa T , Ibrahim Z A , Igarashi Y , Ignatov F V , Iio M , Ishibashi K , Issadykov A , Itahashi T , Jansen A , Jiang X S , Jonsson P , Kachelhoffer T , Kalinnikov V , Kaneva E , Kapusta F , Katayama H , Kawagoe K , Kawashima R , Kazak N , Kazanin V F , Kemularia O , Khvedelidze A , Koike M , Kormoll T , Kozlov G A , Kozyrev A N , Kravchenko M , Krikler B , Kumsiashvili G , Kuno Y , Kuriyama Y , Kurochkin Y , Kurup A , Lagrange B , Lai J , Lee M J , Li H B , Litchfield R P , Li W G , Loan T , Lomidze D , Lomidze I , Loveridge P , Macharashvili G , Makida Y , Mao Y J , Markin O , Matsuda Y , Melkadze A , Melnik A , Mibe T , Mihara S , Miyamoto N , Miyazaki Y , Mohamad Idris F , Azmi K A Mohamed Kamal , Moiseenko A , Moritsu M , Mori Y , Motoishi T , Nakai H , Nakai Y , Nakamoto T , Nakamura Y , Nakatsugawa Y , Nakazawa Y , Nash J , Natori H , Niess V , Nioradze M , Nishiguchi H , Noguchi K , Numao T , O’Dell J , Ogitsu T , Ohta S , Oishi K , Okamoto K , Okamura T , Okinaka K , Omori C , Ota T , Pasternak J , Paulau A , Picters D , Ponariadov V , Quémener G , Ruban A A , Rusinov V , Sabirov B , Sakamoto H , Sarin P , Sasaki K , Sato A , Sato J , Semertzidis Y K , Shigyo N , Shoukavy Dz , Slunecka M , Stöckinger D , Sugano M , Tachimoto T , Takayanagi T , Tanaka M , Tang J , Tao C V , Teixeira A M , Tevzadze Y , Thanh T , Tojo J , Tolmachev S S , Tomasek M , Tomizawa M , Toriashvili T , Trang H , Trekov I , Tsamalaidze Z , Tsverava N , Uchida T , Uchida Y , Ueno K , Velicheva E , Volkov A , Vrba V , Abdullah W A T Wan , Warin-Charpentier P , Wong M L , Wong T S , Wu C , Xing T Y , Yamaguchi H , Yamamoto A , Yamanaka M , Yamane T , Yang Y , Yano T , Yao W C , Yeo B , Yoshida H , Yoshida M , Yoshioka T , Yuan Y , Yudin Yu V , Zdorovets M V , Zhang J , Zhang Y , Zuber K 
Published: October 2019

Abstract
The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminum nucleus ($\mu$–$e$ conversion, $\mu^{-}N \rightarrow e^{-}N$); a lepton flavor-violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90% upper limit of a branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the $\mu$–$e$ conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.