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arXiv · 2403.12520

First Measurement of the $\nu_e$ and $\nu_\mu$ Interaction Cross Sections at the LHC with FASER's Emulsion Detector

FASER Collaboration·Roshan Mammen Abraham·John Anders·Claire Antel·Akitaka Ariga·Tomoko Ariga·Jeremy Atkinson·Florian U. Bernlochner·Tobias Boeckh·Jamie Boyd·Lydia Brenner·Angela Burger·Franck Cadoux·Roberto Cardella·David W. Casper·Charlotte Cavanagh·Xin Chen·Andrea Coccaro·Stephane Debieux·Monica D'Onofrio·Ansh Desai·Sergey Dmitrievsky·Sinead Eley·Yannick Favre·Deion Fellers·Jonathan L. Feng·Carlo Alberto Fenoglio·Didier Ferrere·Max Fieg·Wissal Filali·Haruhi Fujimori·Ali Garabaglu·Stephen Gibson·Sergio Gonzalez-Sevilla·Yuri Gornushkin·Carl Gwilliam·Daiki Hayakawa·Shih-Chieh Hsu·Zhen Hu·Giuseppe Iacobucci·Tomohiro Inada·Luca Iodice·Sune Jakobsen·Hans Joos·Enrique Kajomovitz·Takumi Kanai·Hiroaki Kawahara·Alex Keyken·Felix Kling·Daniela Kock·Pantelis Kontaxakis·Umut Kose·Rafaella Kotitsa·Susanne Kuehn·Thanushan Kugathasan·Helena Lefebvre·Lorne Levinson·Ke Li·Jinfeng Liu·Margaret S. Lutz·Jack MacDonald·Chiara Magliocca·Fulvio Martinelli·Lawson McCoy·Josh McFayden·Andrea Pizarro Medina·Matteo Milanesio·Theo Moretti·Magdalena Munker·Mitsuhiro Nakamura·Toshiyuki Nakano·Friedemann Neuhaus·Laurie Nevay·Motoya Nonaka·Kazuaki Okui·Ken Ohashi·Hidetoshi Otono·Hao Pang·Lorenzo Paolozzi·Brian Petersen·Markus Prim·Michaela Queitsch-Maitland·Hiroki Rokujo·Elisa Ruiz-Choliz·André Rubbia·Jorge Sabater-Iglesias·Osamu Sato·Paola Scampoli·Kristof Schmieden·Matthias Schott·Anna Sfyrla·Mansoora Shamim·Savannah Shively·Yosuke Takubo·Noshin Tarannum·Ondrej Theiner·Eric Torrence·Svetlana Vasina·Benedikt Vormwald·Di Wang

Abstract

This paper presents the first results of the study of high-energy electron and muon neutrino charged-current interactions in the FASER$\nu$ emulsion/tungsten detector of the FASER experiment at the LHC. A subset of the FASER$\nu$ volume, which corresponds to a target mass of 128.6~kg, was exposed to neutrinos from the LHC $pp$ collisions with a centre-of-mass energy of 13.6~TeV and an integrated luminosity of 9.5 fb$^{-1}$. Applying stringent selections requiring electrons with reconstructed energy above 200~GeV, four electron neutrino interaction candidate events are observed with an expected background of $0.025^{+0.015}_{-0.010}$, leading to a statistical significance of 5.2$\sigma$. This is the first direct observation of electron neutrino interactions at a particle collider. Eight muon neutrino interaction candidate events are also detected, with an expected background of $0.22^{+0.09}_{-0.07}$, leading to a statistical significance of 5.7$\sigma$. The signal events include neutrinos with energies in the TeV range, the highest-energy electron and muon neutrinos ever detected from an artificial source. The energy-independent part of the interaction cross section per nucleon is measured over an energy range of 560--1740 GeV (520--1760 GeV) for $\nu_e$ ($\nu_{\mu}$) to be $(1.2_{-0.7}^{+0.8}) \times 10^{-38}~\mathrm{cm}^{2}\,\mathrm{GeV}^{-1}$ ($(0.5\pm0.2) \times 10^{-38}~\mathrm{cm}^{2}\,\mathrm{GeV}^{-1}$), consistent with Standard Model predictions. These are the first measurements of neutrino interaction cross sections in those energy ranges.

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FASER Collaboration, Roshan Mammen Abraham, John Anders, Claire Antel, Akitaka Ariga, Tomoko Ariga, Jeremy Atkinson, Florian U. Bernlochner, Tobias Boeckh, Jamie Boyd, Lydia Brenner, Angela Burger, Franck Cadoux, Roberto Cardella, David W. Casper, Charlotte Cavanagh, Xin Chen, Andrea Coccaro, Stephane Debieux, Monica D'Onofrio, Ansh Desai, Sergey Dmitrievsky, Sinead Eley, Yannick Favre, Deion Fellers, Jonathan L. Feng, Carlo Alberto Fenoglio, Didier Ferrere, Max Fieg, Wissal Filali, Haruhi Fujimori, Ali Garabaglu, Stephen Gibson, Sergio Gonzalez-Sevilla, Yuri Gornushkin, Carl Gwilliam, Daiki Hayakawa, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Luca Iodice, Sune Jakobsen, Hans Joos, Enrique Kajomovitz, Takumi Kanai, Hiroaki Kawahara, Alex Keyken, Felix Kling, Daniela Kock, Pantelis Kontaxakis, Umut Kose, Rafaella Kotitsa, Susanne Kuehn, Thanushan Kugathasan, Helena Lefebvre, Lorne Levinson, Ke Li, Jinfeng Liu, Margaret S. Lutz, Jack MacDonald, Chiara Magliocca, Fulvio Martinelli, Lawson McCoy, Josh McFayden, Andrea Pizarro Medina, Matteo Milanesio, Theo Moretti, Magdalena Munker, Mitsuhiro Nakamura, Toshiyuki Nakano, Friedemann Neuhaus, Laurie Nevay, Motoya Nonaka, Kazuaki Okui, Ken Ohashi, Hidetoshi Otono, Hao Pang, Lorenzo Paolozzi, Brian Petersen, Markus Prim, Michaela Queitsch-Maitland, Hiroki Rokujo, Elisa Ruiz-Choliz, André Rubbia, Jorge Sabater-Iglesias, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Mansoora Shamim, Savannah Shively, Yosuke Takubo, Noshin Tarannum, Ondrej Theiner, Eric Torrence, Svetlana Vasina, Benedikt Vormwald, Di Wang. 2024-03-19. First Measurement of the $\nu_e$ and $\nu_\mu$ Interaction Cross Sections at the LHC with FASER's Emulsion Detector. https://doi.org/10.1103/physrevlett.133.021802

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