Eur. Phys. J. C (2020) 80: 284
https://doi.org/10.1140/epjc/s10052-020-7788-y

Regular Article - Experimental Physics

Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target

¹ Faculty of Physics, Sofia University, Sofia, Bulgaria
² Universidad Técnica Federico Santa María and Centro Científico Tecnológico de Valparaíso, Valparaíso, Chile
³ Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
⁴ LAL, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France
⁵ LPNHE, IN2P3/CNRS, Sorbonne Université, Université Paris Diderot, 75252, Paris, France
⁶ Humboldt-Universität zu Berlin, Berlin, Germany
⁷ Physikalisches Institut, Universität Bonn, Bonn, Germany
⁸ Universität Hamburg, Hamburg, Germany
⁹ Forschungszentrum Jülich GmbH (KFA), Jülich, Germany
¹⁰ Institut für Physik and PRISMA Cluster of Excellence, Johannes Gutenberg Universität Mainz, Mainz, Germany
¹¹ Sezione INFN di Bari, Bari, Italy
¹² Sezione INFN di Bologna, Bologna, Italy
¹³ Sezione INFN di Cagliari, Cagliari, Italy
¹⁴ Sezione INFN di Napoli, Naples, Italy
¹⁵ Laboratori Nazionali dell’INFN di Frascati, Frascati, Italy
¹⁶ Laboratori Nazionali dell’INFN di Gran Sasso, L’Aquila, Italy
¹⁷ Aichi University of Education, Kariya, Japan
¹⁸ Kobe University, Kobe, Japan
¹⁹ Nagoya University, Nagoya, Japan
²⁰ College of Industrial Technology, Nihon University, Narashino, Japan
²¹ Toho University, Funabashi, Chiba, Japan
²² Physics Education Department & RINS, Gyeongsang National University, Jinju, Korea
²³ Gwangju National University of Education, Gwangju, Korea
²⁴ Jeju National University, Jeju, Korea
²⁵ Korea University, Seoul, Korea
²⁶ Sungkyunkwan University, Suwon-si, Gyeong Gi-do, Korea
²⁷ University of Leiden, Leiden, The Netherlands
²⁸ LIP-Laboratory of Instrumentation and Experimental Particle Physics, Lisbon, Portugal
²⁹ Joint Institute for Nuclear Research (JINR), Dubna, Russia
³⁰ Institute of Theoretical and Experimental Physics (ITEP) NRC ‘Kurchatov Institute’, Moscow, Russia
³¹ Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS), Moscow, Russia
³² P.N. Lebedev Physical Institute (LPI RAS), Moscow, Russia
³³ National Research Centre ‘Kurchatov Institute’, Moscow, Russia
³⁴ National University of Science and Technology “MISiS”, Moscow, Russia
³⁵ Institute for High Energy Physics (IHEP) NRC ‘Kurchatov Institute’, Protvino, Russia
³⁶ Petersburg Nuclear Physics Institute (PNPI) NRC ‘Kurchatov Institute’, Gatchina, Russia
³⁷ St. Petersburg Polytechnic University (SPbPU), Saint Petersburg, Russia
³⁸ National Research Nuclear University (MEPhI), Moscow, Russia
³⁹ Skobeltsyn Institute of Nuclear Physics of Moscow State University (SINP MSU), Moscow, Russia
⁴⁰ Yandex School of Data Analysis, Moscow, Russia
⁴¹ Institute of Physics, University of Belgrade, Serbia
⁴² Stockholm University, Stockholm, Sweden
⁴³ Uppsala University, Uppsala, Sweden
⁴⁴ European Organization for Nuclear Research (CERN), Geneva, Switzerland
⁴⁵ University of Geneva, Geneva, Switzerland
⁴⁶ École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
⁴⁷ Physik-Institut, Universität Zürich, Zürich, Switzerland
⁴⁸ Middle East Technical University (METU), Ankara, Turkey
⁴⁹ Ankara University, Ankara, Turkey
⁵⁰ H.H. Wills Physics Laboratory, University of Bristol, Bristol, UK
⁵¹ STFC Rutherford Appleton Laboratory, Didcot, UK
⁵² Imperial College London, London, UK
⁵³ University College London, London, UK
⁵⁴ University of Warwick, Warwick, UK
⁵⁵ Taras Shevchenko National University of Kyiv, Kyiv, Ukraine

^* e-mail: eric.van.herwijnen@cern.ch

Received: 27 January 2020
Accepted: 27 February 2020
Published online: 29 March 2020

Abstract

The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to protons on target was recorded. This amounts to approximatively 1% of a SHiP spill.