Eur. Phys. J. C (2020) 80: 61
https://doi.org/10.1140/epjc/s10052-020-7631-5

Regular Article - Experimental Physics

Detecting and studying high-energy collider neutrinos with FASER at the LHC

FASER Collaboration

¹ Department of Physics and Astronomy, Technion-Israel Institute of Technology, 32000, Haifa, Israel
² Département de Physique Nucléaire et Corpusculaire, University of Geneva, 1211, Geneva 4, Switzerland
³ Universität Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
⁴ Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
⁵ CERN, 1211, Geneva 23, Switzerland
⁶ Department of Physics and Astronomy, University of California, Irvine, CA, 92697-4575, USA
⁷ Physics Department, Tsinghua University, Beijing, China
⁸ INFN Sezione di Genova, Via Dodecaneso, 33, 16146, Genoa, Italy
⁹ Department of Physics, Brookhaven National Laboratory, Upton, NY, 11973, USA
¹⁰ New High Energy Theory Center, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854-8019, USA
¹¹ Royal Holloway, University of London, Egham, TW20 0EX, UK
¹² Department of Physics, University of Washington, PO Box 351560, Seattle, WA, 98195-1560, USA
¹³ SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
¹⁴ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100, Rehovot, Israel
¹⁵ Institut für Physik, Universität Mainz, Mainz, Germany
¹⁶ Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
¹⁷ Institute of Particle and Nuclear Study, KEK, Oho 1-1, Tsukuba, Ibaraki, 305-0801, Japan
¹⁸ University of Oregon, Eugene, OR, 97403, USA
¹⁹ Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK

^* e-mail: akitaka.ariga@lhep.unibe.ch

Received: 15 August 2019
Accepted: 8 January 2020
Published online: 25 January 2020

Abstract

Neutrinos are copiously produced at particle colliders, but no collider neutrino has ever been detected. Colliders produce both neutrinos and anti-neutrinos of all flavors at very high energies, and they are therefore highly complementary to those from other sources. FASER, the Forward Search Experiment at the LHC, is ideally located to provide the first detection and study of collider neutrinos. We investigate the prospects for neutrino studies with FASER, a proposed component of FASER, consisting of emulsion films interleaved with tungsten plates with a total target mass of 1.2 t, to be placed on-axis at the front of FASER. We estimate the neutrino fluxes and interaction rates, describe the FASER detector, and analyze the characteristics of the signals and primary backgrounds. For an integrated luminosity of to be collected during Run 3 of the 14 TeV LHC in 2021–23, approximately 1300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASER, with mean energies of 600 GeV to 1 TeV. With such rates and energies, FASER will measure neutrino cross sections at energies where they are currently unconstrained, will bound models of forward particle production, and could open a new window on physics beyond the standard model.