The design of the MEG II experiment

The European Physical Journal C - Tập 78 - Trang 1-60 - 2018
A. M. Baldini1, E. Baracchini2, C. Bemporad1, F. Berg3,4, M. Biasotti5, G. Boca6, P. W. Cattaneo6, G. Cavoto7, F. Cei1, M. Chiappini1,8, G. Chiarello9, C. Chiri9, G. Cocciolo9, A. Corvaglia9, A. de Bari6, M. De Gerone5, A. D’Onofrio1, M. Francesconi1, Y. Fujii2, L. Galli1, F. Gatti5, F. Grancagnolo9, M. Grassi1, D. N. Grigoriev10,11,12, M. Hildebrandt3, Z. Hodge13,4, K. Ieki2, F. Ignatov10,12, R. Iwai2, T. Iwamoto2, D. Kaneko2, K. Kasami14, P.-R. Kettle3, B. I. Khazin10,12, N. Khomutov15, A. Korenchenko15, N. Kravchuk15, T. Libeiro16, M. Maki14, N. Matsuzawa2, S. Mihara14, M. Milgie16, W. Molzon16, Toshinori Mori2, F. Morsani1, A. Mtchedilishvili13, M. Nakao2, S. Nakaura2, D. Nicolò1, H. Nishiguchi14, M. Nishimura2, S. Ogawa2, W. Ootani2, M. Panareo9, A. Papa3, A. Pepino9, G. Piredda7, A. Popov10,12, F. Raffaelli1, F. Renga7, E. Ripiccini7, S. Ritt3, M. Rossella6, G. Rutar3,4, R. Sawada2, G. Signorelli1, M. Simonetta6, G. F. Tassielli9, Y. Uchiyama2, M. Usami2, M. Venturini1, C. Voena7, K. Yoshida2, Yu. V. Yudin10,12, Y. Zhang16
1INFN Sezione di Pisa; Dipartimento di Fisica, dell’Università, Largo B. Pontecorvo 3, 56127 Pisa; Scuola Normale Superiore, Pisa, Italy
2ICEPP, The University of Tokyo, Bunkyo-ku, Japan
3Paul Scherrer Institut PSI, Villigen, Switzerland
4Swiss Federal Institute of Technology, ETH Zurich, Switzerland
5INFN Sezione di Genova; Dipartimento di Fisica, dell’Università, Genoa, Italy
6INFN Sezione di Pavia; Dipartimento di Fisica, dell’Università, Pavia, Italy
7INFN Sezione di Roma; Dipartimento di Fisica, dell’Università “Sapienza”, Rome, Italy
8Dipartimento di Scienze Fisiche, della Terra e dell’Ambiente dell’Università, Siena, Italy
9INFN Sezione di Lecce; Dipartimento di Matematica e Fisica, dell’Università del Salento, Lecce, Italy
10Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
11Novosibirsk State Technical University, Novosibirsk, Russia
12Novosibirsk State University, Novosibirsk, Russia
13Paul-Scherrer-Institut (PSI), Villigen, Switzerland
14KEK, High Energy Accelerator Research Organization 1-1 Oho, Tsukuba, Japan
15Joint Institute for Nuclear research, Dubna, Russia
16University of California, Irvine, USA

Tóm tắt

The MEG experiment, designed to search for the $${\mu ^+ \rightarrow \hbox {e}^+ \gamma }$$ decay, completed data-taking in 2013 reaching a sensitivity level of $${5.3\times 10^{-13}}$$ for the branching ratio. In order to increase the sensitivity reach of the experiment by an order of magnitude to the level of $$6\times 10^{-14}$$ , a total upgrade, involving substantial changes to the experiment, has been undertaken, known as MEG II. We present both the motivation for the upgrade and a detailed overview of the design of the experiment and of the expected detector performance.

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