Eur. Phys. J. C (2019) 79: 257
https://doi.org/10.1140/epjc/s10052-019-6674-y

Regular Article - Experimental Physics

First particle-by-particle measurement of emittance in the Muon Ionization Cooling Experiment

¹ Department of Atomic Physics, St. Kliment Ohridski University of Sofia, Sofia, Bulgaria
² Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
³ Sichuan University, Chengdu, China
⁴ Dipartimento di Fisica G. Occhialini, Sezione INFN Milano Bicocca, Milan, Italy
⁵ Sezione INFN Napoli and Dipartimento di Fisica, Università Federico II, Complesso Universitario di Monte S. Angelo, Naples, Italy
⁶ Sezione INFN Pavia and Dipartimento di Fisica, Pavia, Italy
⁷ INFN Sezione di Roma Tre and Dipartimento di Matematica e Fisica, Università Roma Tre, Rome, Italy
⁸ Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
⁹ High Energy Accelerator Research Organization (KEK), Institute of Particle and Nuclear Studies, Tsukuba, Ibaraki, Japan
¹⁰ UNIST, Ulsan, Korea
¹¹ Nikhef, Amsterdam, The Netherlands
¹² Institute of Physics, University of Belgrade, Belgrade, Serbia
¹³ DPNC, Section de Physique, Université de Genève, Geneva, Switzerland
¹⁴ STFC Daresbury Laboratory, Daresbury, Cheshire, UK
¹⁵ STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, UK
¹⁶ School of Physics and Astronomy, The University of Glasgow, Kelvin Building, Glasgow, UK
¹⁷ Department of Physics, University of Liverpool, Liverpool, UK
¹⁸ Blackett Laboratory, Department of Physics, Imperial College London, London, UK
¹⁹ Department of Physics, University of Oxford, Denys Wilkinson Building, Oxford, UK
²⁰ Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
²¹ SUPA and the Department of Physics, University of Strathclyde, Glasgow, UK
²² Department of Physics, University of Warwick, Coventry, UK
²³ Brunel University, Uxbridge, UK
²⁴ Brookhaven National Laboratory, Upton, NY, USA
²⁵ Fermilab, Batavia, IL, USA
²⁶ Lawrence Berkeley National Laboratory, Berkeley, CA, USA
²⁷ Illinois Institute of Technology, Chicago, IL, USA
²⁸ University of Mississippi, Oxford, MS, USA
²⁹ University of California, Riverside, CA, USA
³⁰ University of California, Los Angeles, CA, USA
³¹ Present address: RIKEN, Wako, Japan
³² Radboud University, Nijmegen, The Netherlands
³³ Present address: Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
³⁴ Present address: Institute of High Energy Physics, Chinese Academy of Sciences, Bejing, China

^* e-mail: v.blackmore@imperial.ac.uk

Received: 31 October 2018
Accepted: 11 February 2019
Published online: 21 March 2019

Abstract

The Muon Ionization Cooling Experiment (MICE) collaboration seeks to demonstrate the feasibility of ionization cooling, the technique by which it is proposed to cool the muon beam at a future neutrino factory or muon collider. The emittance is measured from an ensemble of muons assembled from those that pass through the experiment. A pure muon ensemble is selected using a particle-identification system that can reject efficiently both pions and electrons. The position and momentum of each muon are measured using a high-precision scintillating-fibre tracker in a 4 T solenoidal magnetic field. This paper presents the techniques used to reconstruct the phase-space distributions in the upstream tracking detector and reports the first particle-by-particle measurement of the emittance of the MICE Muon Beam as a function of muon-beam momentum.