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arXiv · 2602.17575

Momentum Measurement of Charged Particles in FASER's Emulsion Detector at the LHC

FASER Collaboration·Roshan Mammen Abraham·Xiaocong Ai·Saul Alonso Monsalve·John Anders·Emma Kate Anderson·Claire Antel·Akitaka Ariga·Tomoko Ariga·Jeremy Atkinson·Florian U. Bernlochner·Tobias Boeckh·Eliot Bornand·Jamie Boyd·Lydia Brenner·Angela Burger·Franck Cadoux·Roberto Cardella·David W. Casper·Charlotte Cavanagh·Shiyang Chen·Xin Chen·Xing Cheng·Kohei Chinone·Dhruv Chouhan·Andrea Coccaro·Stephane Débieux·Ansh Desai·Sergey Dmitrievsky·Radu Dobre·Monica D'Onofrio·Sinead Eley·Yannick Favre·Jonathan L. Feng·Carlo Alberto Fenoglio·Didier Ferrere·Max Fieg·Wissal Filali·Elena Firu·Haruhi Fujimori·Edward Galantay·Ali Garabaglu·Stephen Gibson·Sergio Gonzalez-Sevilla·Yuri Gornushkin·Yotam Granov·Jinjing Gu·Carl Gwilliam·Elie Hammou·Daiki Hayakawa·Michael Holzbock·Shih-Chieh Hsu·Zhen Hu·Giuseppe Iacobucci·Tomohiro Inada·Luca Iodice·Sune Jakobsen·Cesar Jesus-Valls·Arash Jofrehei·Hans Joos·Enrique Kajomovitz·Takumi Kanai·Hiroaki Kawahara·Alex Keyken·Felix Kling·Daniela Köck·Pantelis Kontaxakis·Jelle Koorn·Umut Kose·Peter Krack·Susanne Kuehn·Thanushan Kugathasan·Sebastian Laudage·Lorne Levinson·Botao Li·Jinfeng Liu·Yi Liu·Margaret S. Lutz·Jack MacDonald·Joern Mahlstedt·Toni Mäkelä·Anna Mascellani·Lawson McCoy·Josh McFayden·Andrea Pizarro Medina·Théo Moretti·Keiko Moriyama·Toshiyuki Nakano·Laurie Nevay·Motoya Nonaka·Yuma Ohara·Ken Ohashi·Kazuaki Okui·Hidetoshi Otono·Lorenzo Paolozzi·Annabelle Parry·Pawan Pawan·Brian Petersen·Titi Preda·Markus Prim

Abstract

We present a momentum measurement method based on multiple Coulomb scattering (MCS) in the FASER$\nu$ emulsion detector. The measurement of charged-particle momenta is essential for studying neutrino interactions in the TeV energy range at the FASER experiment. This method exploits the sub-micron spatial resolution and long tracking length of the FASER$\nu$ detector, enabling momentum determination from a few GeV up to a few TeV. The performance was evaluated using Geant4-based Monte Carlo simulations and validated with muon test beam data in the momentum range 100-300 GeV. As a first probe of the method for higher momentum muons, background muons recorded by the FASER$\nu$ detector were examined, showing reconstructed momenta consistent with expectations from their angular spread.

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FASER Collaboration, Roshan Mammen Abraham, Xiaocong Ai, Saul Alonso Monsalve, John Anders, Emma Kate Anderson, Claire Antel, Akitaka Ariga, Tomoko Ariga, Jeremy Atkinson, Florian U. Bernlochner, Tobias Boeckh, Eliot Bornand, Jamie Boyd, Lydia Brenner, Angela Burger, Franck Cadoux, Roberto Cardella, David W. Casper, Charlotte Cavanagh, Shiyang Chen, Xin Chen, Xing Cheng, Kohei Chinone, Dhruv Chouhan, Andrea Coccaro, Stephane Débieux, Ansh Desai, Sergey Dmitrievsky, Radu Dobre, Monica D'Onofrio, Sinead Eley, Yannick Favre, Jonathan L. Feng, Carlo Alberto Fenoglio, Didier Ferrere, Max Fieg, Wissal Filali, Elena Firu, Haruhi Fujimori, Edward Galantay, Ali Garabaglu, Stephen Gibson, Sergio Gonzalez-Sevilla, Yuri Gornushkin, Yotam Granov, Jinjing Gu, Carl Gwilliam, Elie Hammou, Daiki Hayakawa, Michael Holzbock, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Luca Iodice, Sune Jakobsen, Cesar Jesus-Valls, Arash Jofrehei, Hans Joos, Enrique Kajomovitz, Takumi Kanai, Hiroaki Kawahara, Alex Keyken, Felix Kling, Daniela Köck, Pantelis Kontaxakis, Jelle Koorn, Umut Kose, Peter Krack, Susanne Kuehn, Thanushan Kugathasan, Sebastian Laudage, Lorne Levinson, Botao Li, Jinfeng Liu, Yi Liu, Margaret S. Lutz, Jack MacDonald, Joern Mahlstedt, Toni Mäkelä, Anna Mascellani, Lawson McCoy, Josh McFayden, Andrea Pizarro Medina, Théo Moretti, Keiko Moriyama, Toshiyuki Nakano, Laurie Nevay, Motoya Nonaka, Yuma Ohara, Ken Ohashi, Kazuaki Okui, Hidetoshi Otono, Lorenzo Paolozzi, Annabelle Parry, Pawan Pawan, Brian Petersen, Titi Preda, Markus Prim. 2026-02-19. Momentum Measurement of Charged Particles in FASER's Emulsion Detector at the LHC. https://arxiv.org/abs/2602.17575

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