FASER Collaboration, Akitaka Ariga, Tomoko Ariga, Jamie Boyd, David W. Casper, Jonathan L. Feng, Iftah Galon, Shih-Chieh Hsu, Felix Kling, Hidetoshi Otono, Brian Petersen, Osamu Sato, Aaron M. Soffa, Jeffrey R. Swaney, Sebastian Trojanowski
FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles at the LHC. Such particles are dominantly produced along the beam collision axis and may be long-lived, traveling hundreds of meters before decaying. To exploit both of these properties, FASER is to be located along the beam collision axis, 480 m downstream from the ATLAS interaction point, in the unused service tunnel TI18. We propose that FASER be installed in TI18 in Long Shutdown 2 in time to collect data from 2021-23 during Run 3 of the 14 TeV LHC. FASER will detect new particles that decay within a cylindrical volume with radius R= 10 cm and length L = 1.5 m. With these small dimensions, FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new particles, including dark photons, axion-like particles, and other CP-odd scalars. A FLUKA simulation and analytical estimates have confirmed that numerous potential backgrounds are highly suppressed at the FASER location, and the first in situ measurements are currently underway. We describe FASER's location and discovery potential, its target signals and backgrounds, the detector's layout and components, and the experiment's preliminary cost estimate, funding, and timeline.
FASER Collaboration, Akitaka Ariga, Tomoko Ariga, Jamie Boyd, Franck Cadoux, David W. Casper, Yannick Favre, Jonathan L. Feng, Didier Ferrere, Iftah Galon, Sergio Gonzalez-Sevilla, Shih-Chieh Hsu, Giuseppe Iacobucci, Enrique Kajomovitz, Felix Kling, Susanne Kuehn, Lorne Levinson, Hidetoshi Otono, Brian Petersen, Osamu Sato, Matthias Schott, Anna Sfyrla, Jordan Smolinsky, Aaron M. Soffa, Yosuke Takubo, Eric Torrence, Sebastian Trojanowski, Gang Zhang
FASER,the ForwArd Search ExpeRiment,is a proposed experiment dedicated to searching for light, extremely weakly-interacting particles at the LHC. Such particles may be produced in the LHC's high-energy collisions and travel long distances through concrete and rock without interacting. They may then decay to visible particles in FASER, which is placed 480 m downstream of the ATLAS interaction point. In this work we briefly describe the FASER detector layout and the status of potential backgrounds. We then present the sensitivity reach for FASER for a large number of long-lived particle models, updating previous results to a uniform set of detector assumptions, and analyzing new models. In particular, we consider all of the renormalizable portal interactions, leading to dark photons, dark Higgs bosons, and heavy neutral leptons (HNLs); light B-L and $L_i - L_j$ gauge bosons; axion-like particles (ALPs) that are coupled dominantly to photons, fermions, and gluons through non-renormalizable operators; and pseudoscalars with Yukawa-like couplings. We find that FASER and its follow-up, FASER 2, have a full physics program, with discovery sensitivity in all of these models and potentially far-reaching implications for particle physics and cosmology.
FASER Collaboration, Akitaka Ariga, Tomoko Ariga, Jamie Boyd, Franck Cadoux, David W. Casper, Francesco Cerutti, Salvatore Danzeca, Liam Dougherty, Yannick Favre, Jonathan L. Feng, Didier Ferrere, Jonathan Gall, Iftah Galon, Sergio Gonzalez-Sevilla, Shih-Chieh Hsu, Giuseppe Iacobucci, Enrique Kajomovitz, Felix Kling, Susanne Kuehn, Mike Lamont, Lorne Levinson, Hidetoshi Otono, John Osborne, Brian Petersen, Osamu Sato, Marta Sabate-Gilarte, Matthias Schott, Anna Sfyrla, Jordan Smolinsky, Aaron M. Soffa, Yosuke Takubo, Pierre Thonet, Eric Torrence, Sebastian Trojanowski, Gang Zhang
FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment.
FASER Collaboration, Henso Abreu, Claire Antel, Akitaka Ariga, Tomoko Ariga, Jamie Boyd, Franck Cadoux, David W. Casper, Xin Chen, Andrea Coccaro, Candan Dozen, Peter B. Denton, Yannick Favre, Jonathan L. Feng, Didier Ferrere, Iftah Galon, Stephen Gibson, Sergio Gonzalez-Sevilla, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Sune Jakobsen, Roland Jansky, Enrique Kajomovitz, Felix Kling, Susanne Kuehn, Lorne Levinson, Congqiao Li, 1 Josh McFayden, Sam Meehan, Friedemann Neuhaus, Hidetoshi Otono, Brian Petersen, Helena Pikhartova, Michaela Queitsch-Maitland, Osamu Sato, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Savannah Shively, Jordan Smolinsky, Aaron M. Soffa, Yosuke Takubo, Eric Torrence, Sebastian Trojanowski, Callum Wilkinson, Dengfeng Zhang, Gang Zhang
Neutrinos are copiously produced at particle colliders, but no collider neutrino has ever been detected. Colliders, and particularly hadron 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 recently approved Forward Search Experiment at the Large Hadron Collider, is ideally located to provide the first detection and study of collider neutrinos. We investigate the prospects for neutrino studies of a proposed component of FASER, FASER$ν$, a 25cm x 25cm x 1.35m emulsion detector to be placed directly in front of the FASER spectrometer in tunnel TI12. FASER$ν$ consists of 1000 layers of emulsion films interleaved with 1-mm-thick tungsten plates, with a total tungsten target mass of 1.2 tons. We estimate the neutrino fluxes and interaction rates at FASER$ν$, describe the FASER$ν$ detector, and analyze the characteristics of the signals and primary backgrounds. For an integrated luminosity of 150 fb$^{-1}$ to be collected during Run 3 of the 14 TeV Large Hadron Collider from 2021-23, and assuming standard model cross sections, approximately 1300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASER$ν$, with mean energies of 600 GeV to 1 TeV, depending on the flavor. 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.
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, Yuxiao Wang, Eli Welch, Samuel Zahorec, Stefano Zambito, Shunliang Zhang
This paper presents the first results of the study of high-energy electron and muon neutrino charged-current interactions in the FASER$ν$ emulsion/tungsten detector of the FASER experiment at the LHC. A subset of the FASER$ν$ 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$σ$. 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$σ$. 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 $ν_e$ ($ν_μ$) 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.
FASER Collaboration, Henso Abreu, Yoav Afik, Claire Antel, Jason Arakawa, Akitaka Ariga, Tomoko Ariga, Florian Bernlochner, Tobias Boeckh, Jamie Boyd, Lydia Brenner, Franck Cadoux, David W. Casper, Charlotte Cavanagh, Francesco Cerutti, Xin Chen, Andrea Coccaro, Monica D'Onofrio, Candan Dozen, Yannick Favre, Deion Fellers, Jonathan L. Feng, Didier Ferrere, Stephen Gibson, Sergio Gonzalez-Sevilla, Carl Gwilliam, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Ahmed Ismail, Sune Jakobsen, Enrique Kajomovitz, Felix Kling, Umut Kose, Susanne Kuehn, Helena Lefebvre, Lorne Levinson, Ke Li, Jinfeng Liu, Chiara Magliocca, Josh McFayden, Sam Meehan, Dimitar Mladenov, Mitsuhiro Nakamura, Toshiyuki Nakano, Marzio Nessi, Friedemann Neuhaus, Laurie Nevay, Hidetoshi Otono, Carlo Pandini, Hao Pang, Lorenzo Paolozzi, Brian Petersen, Francesco Pietropaolo, Markus Prim, Michaela Queitsch-Maitland, Filippo Resnati, Hiroki Rokujo, Marta Sabaté-Gilarte, Jakob Salfeld-Nebgen, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Savannah Shively, John Spencer, Yosuke Takubo, Ondrej Theiner, Eric Torrence, Sebastian Trojanowski, Serhan Tufanli, Benedikt Vormwald, Di Wang, Gang Zhang
FASER$ν$ at the CERN Large Hadron Collider (LHC) is designed to directly detect collider neutrinos for the first time and study their cross sections at TeV energies, where no such measurements currently exist. In 2018, a pilot detector employing emulsion films was installed in the far-forward region of ATLAS, 480 m from the interaction point, and collected 12.2 fb$^{-1}$ of proton-proton collision data at a center-of-mass energy of 13 TeV. We describe the analysis of this pilot run data and the observation of the first neutrino interaction candidates at the LHC. This milestone paves the way for high-energy neutrino measurements at current and future colliders.
T2K Collaboration, K. Abe, N. Abgrall, Y. Ajima, H. Aihara, J. B. Albert, C. Andreopoulos, B. Andrieu, S. Aoki, O. Araoka, J. Argyriades, A. Ariga, T. Ariga, S. Assylbekov, D. Autiero, A. Badertscher, M. Barbi, G. J. Barker, G. Barr, M. Bass, F. Bay, S. Bentham, V. Berardi, B. E. Berger, I. Bertram, M. Besnier, J. Beucher, D. Beznosko, S. Bhadra, F. d. M. Blaszczyk, A. Blondel, C. Bojechko, J. Bouchez, S. B. Boyd, A. Bravar, C. Bronner, D. G. Brook-Roberge, N. Buchanan, H. Budd, D. Calvet, S. L. Cartwright, A. Carver, R. Castillo, M. G. Catanesi, A. Cazes, A. Cervera, C. Chavez, S. Choi, G. Christodoulou, J. Coleman, W. Coleman, G. Collazuol, K. Connolly, A. Curioni, A. Dabrowska, I. Danko, R. Das, G. S. Davies, S. Davis, M. Day, G. DeRosa, J. P. A. M. de Andre, P. dePerio, A. Delbart, C. Densham, F. DiLodovico, S. DiLuise, P. Dinh Tran, J. Dobson, U. Dore, O. Drapier, F. Dufour, J. Dumarchez, S. Dytman, M. Dziewiecki, M. Dziomba, S. Emery, A. Ereditato, L. Escudero, L. S. 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Murdoch, S. Murphy, J. Myslik, T. Nakadaira, M. Nakahata, T. Nakai, K. Nakajima, T. Nakamoto, K. Nakamura, S. Nakayama, T. Nakaya, D. Naples, M. L. Navin, B. Nelson, T. C. Nicholls, K. Nishikawa, H. Nishino, J. A. Nowak, M. Noy, Y. Obayashi, T. Ogitsu, H. Ohhata, T. Okamura, K. Okumura, T. Okusawa, S. M. Oser, M. Otani, R. A. Owen, Y. Oyama, T. Ozaki, M. Y. Pac, V. Palladino, V. Paolone, P. Paul, D. Payne, G. F. Pearce, J. D. Perkin, V. Pettinacci, F. Pierre, E. Poplawska, B. Popov, M. Posiadala, J. -M. Poutissou, R. Poutissou, P. Przewlocki, W. Qian, J. L. Raaf, E. Radicioni, P. N. Ratoff, T. M. Raufer, M. Ravonel, M. Raymond, F. Retiere, A. Robert, P. A. Rodrigues, E. Rondio, J. M. Roney, B. Rossi, S. Roth, A. Rubbia, D. Ruterbories, S. Sabouri, R. Sacco, K. Sakashita, F. Sanchez, A. Sarrat, K. Sasaki, K. Scholberg, J. Schwehr, M. Scott, D. I. Scully, Y. Seiya, T. Sekiguchi, H. Sekiya, M. Shibata, Y. Shimizu, M. Shiozawa, S. Short, M. Syiad, R. J. Smith, M. Smy, J. T. Sobczyk, H. 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Zambelli, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, J. Zmuda
OPERA Collaboration, N. Agafonova, A. Aleksandrov, A. Anokhina, S. Aoki, A. Ariga, T. Ariga, T. Asada, D. Autiero, A. Badertscher, A. Ben Dhahbi, D. Bender, A. Bertolin, C. Bozza, R. Brugnera, G. Brunetti, B. Buettner, S. Buontempo, L. Chaussard, M. Chernyavskiy, V. Chiarella, A. Chukanov, L. Consiglio, N. D'Ambrosio, P. Del Amo Sanchez, G. De Lellis, M. De Serio, A. Di Crescenzo, D. Di Ferdinando, N. Di Marco, S. Dmitrievski, M. Dracos, D. Duchesneau, S. Dusini, J. Ebert, A. Ereditato, J. Favier, T. Ferber, R. A. Fini, T. Fukuda, A. Garfagnini, G. Giacomelli, C. Goellnitz, J. Goldberg, Y. Gornushkin, G. Grella, F. Grianti, A. M. Guler, C. Gustavino, C. Hagner, K. Hakamata, T. Hara, T. Hayakawa, M. Hierholzer, A. Hollnagel, B. Hosseini, H. Ishida, K. Ishiguro, M. Ishikawa, K. Jakovcic, C. Jollet, C. Kamiscioglu, M. Kamiscioglu, T. Katsuragawa, H. Kawahara, J. Kawada, J. H. Kim, S. H. Kim, M. Kimura, N. Kitagawa, B. Klicek, K. Kodama, M. Komatsu, U. Kose, I. Kreslo, A. Lauria, J. Lenkeit, A. Ljubicic, A. Longhin, P. Loverre, A. Malgin, G. Mandrioli, J. Marteau, T. Matsuo, V. Matveev, N. Mauri, E. Medinaceli, A. Meregaglia, P. Migliozzi, S. Mikado, A. Minotti, M. Miyanishi, E. Miyashita, P. Monacelli, M. C. Montesi, K. Morishima, M. T. Muciaccia, N. Naganawa, T. Naka, M. Nakamura, T. Nakano, Y. Nakatsuka, K. Niwa, S. Ogawa, N. Okateva, A. Olshevsky, T. Omura, K. Ozaki, A. Paoloni, B. D. Park, I. G. Park, A. Pastore, L. Patrizii, E. Pennacchio, H. Pessard, C. Pistillo, D. Podgrudkov, N. Polukhina, M. Pozzato, K. Pretzl, F. Pupilli, R. Rescigno, M. Roda, T. Roganova, H. Rokujo, G. Rosa, I. Rostovtseva, A. Rubbia, A. Russo, O. Ryazhskaya, O. Sato, Y. Sato, A. Schembri, W. Schmidt-Parzefall, I. Shakiryanova, T. Schcedrina, A. Sheshukov, H. Shibuya, T. Shiraishi, G. Shoziyoev, S. Simone, M. Sioli, C. Sirignano, G. Sirri, M. Spinetti, L. Stanco, N. Starkov, S. M. Stellacci, M. Stipcevic, T. Strauss, P. Strolin, K. Suzuki, S. Takahashi, M. Tenti, F. Terranova, V. Tioukov, P. Tolun, S. Tufanli, P. Vilain, M. Vladimirov, L. Votano, J. L. Vuilleumier, G. Wilquet, B. Wonsak, C. S. Yoon, J. Yoshida, M. Yoshimoto, Y. Zaitsev, S. Zemskova, A. Zghiche
T2K Collaboration, K. Abe, N. Abgrall, H. Aihara, Y. Ajima, J. B. Albert, D. Allan, P. -A. Amaudruz, C. Andreopoulos, B. Andrieu, M. D. Anerella, C. Angelsen, S. Aoki, O. Araoka, J. Argyriades, A. Ariga, T. Ariga, S. Assylbekov, J. P. A. M. de André, D. Autiero, A. Badertscher, O. Ballester, M. Barbi, G. J. Barker, P. Baron, G. Barr, L. Bartoszek, M. Batkiewicz, F. Bay, S. Bentham, V. Berardi, B. E. Berger, H. Berns, I. Bertram, M. Besnier, J. Beucher, D. Beznosko, S. Bhadra, P. Birney, D. Bishop, E. Blackmore, F. d. M. Blaszczyk, J. Blocki, A. Blondel, A. Bodek, C. Bojechko, J. Bouchez, T. Boussuge, S. B. Boyd, M. Boyer, N. Braam, R. Bradford, A. Bravar, K. Briggs, J. D. Brinson, C. Bronner, D. G. Brook-Roberge, M. Bryant, N. Buchanan, H. Budd, M. Cadabeschi, R. G. Calland, D. Calvet, J. Caravaca Rodríguez, J. Carroll, S. L. Cartwright, A. Carver, R. Castillo, M. G. Catanesi, C. Cavata, A. Cazes, A. Cervera, J. P. Charrier, C. Chavez, S. Choi, S. Chollet, G. Christodoulou, P. Colas, J. Coleman, W. Coleman, G. Collazuol, K. Connolly, P. Cooke, A. Curioni, A. Dabrowska, I. Danko, R. Das, G. S. Davies, S. Davis, M. Day, X. De La Broise, P. de Perio, G. De Rosa, T. Dealtry, A. Debraine, E. Delagnes, A. Delbart, C. Densham, F. Di Lodovico, S. Di Luise, P. Dinh Tran, J. Dobson, J. Doornbos, U. Dore, O. Drapier, F. Druillole, F. Dufour, J. Dumarchez, T. Durkin, S. Dytman, M. Dziewiecki, M. Dziomba, B. Ellison, S. Emery, A. Ereditato, J. E. Escallier, L. Escudero, L. S. Esposito, W. Faszer, M. Fechner, A. Ferrero, A. Finch, C. Fisher, M. Fitton, R. Flight, D. Forbush, E. Frank, K. Fransham, Y. Fujii, Y. Fukuda, M. Gallop, V. Galymov, G. L. Ganetis, F. C. Gannaway, A. Gaudin, J. Gaweda, A. Gendotti, M. George, S. Giffin, C. Giganti, K. Gilje, I. Giomataris, J. Giraud, A. K. Ghosh, T. Golan, M. Goldhaber, J. J. Gomez-Cadenas, S. Gomi, M. Gonin, M. Goyette, A. Grant, N. Grant, F. Grañena, S. Greenwood, P. Gumplinger, P. Guzowski, M. D. Haigh, K. Hamano, C. Hansen, T. Hara, P. F. Harrison, B. Hartfiel, M. Hartz, T. Haruyama, R. Hasanen, T. Hasegawa, N. C. Hastings, S. Hastings, A. Hatzikoutelis, K. Hayashi, Y. Hayato, T. D. J. Haycock, C. Hearty, R. L. Helmer, R. Henderson, S. Herlant, N. Higashi, J. Hignight, K. Hiraide, E. Hirose, J. Holeczek, N. Honkanen, S. Horikawa, A. Hyndman, A. K. Ichikawa, K. Ieki, M. Ieva, M. Iida, M. Ikeda, J. Ilic, J. Imber, T. Ishida, C. Ishihara, T. Ishii, S. J. Ives, M. Iwasaki, K. Iyogi, A. Izmaylov, B. Jamieson, R. A. Johnson, K. K. Joo, G. Jover-Manas, C. K. Jung, H. Kaji, T. Kajita, H. Kakuno, J. Kameda, K. Kaneyuki, D. Karlen, K. Kasami, V. Kasey, I. Kato, H. Kawamuko, E. Kearns, L. Kellet, M. Khabibullin, M. Khaleeq, N. Khan, A. Khotjantsev, D. Kielczewska, T. Kikawa, J. Y. Kim, S. -B. Kim, N. Kimura, B. Kirby, J. Kisiel, P. Kitching, T. Kobayashi, G. Kogan, S. Koike, T. Komorowski, A. Konaka, L. L. Kormos, A. Korzenev, K. Koseki, Y. Koshio, Y. Kouzuma, K. Kowalik, V. Kravtsov, I. Kreslo, W. Kropp, H. Kubo, J. Kubota, Y. Kudenko, N. Kulkarni, L. Kurchaninov, Y. Kurimoto, R. Kurjata, Y. Kurosawa, T. Kutter, J. Lagoda, K. Laihem, R. Langstaff, M. Laveder, T. B. Lawson, P. T. Le, A. Le Coguie, M. Le Ross, K. P. Lee, M. Lenckowski, C. Licciardi, I. T. Lim, T. Lindner, R. P. Litchfield, A. Longhin, G. D. Lopez, P. Lu, L. Ludovici, T. Lux, M. Macaire, L. Magaletti, K. Mahn, Y. Makida, C. J. Malafis, M. Malek, S. Manly, A. Marchionni, C. Mark, A. D. Marino, A. J. Marone, J. Marteau, J. F. Martin, T. Maruyama, T. Maryon, J. Marzec, P. Masliah, E. L. Mathie, C. Matsumura, K. Matsuoka, V. Matveev, K. Mavrokoridis, E. Mazzucato, N. McCauley, K. S. McFarland, C. McGrew, T. McLachlan, I. Mercer, M. Messina, W. Metcalf, C. Metelko, M. Mezzetto, P. Mijakowski, C. A. Miller, A. Minamino, O. Mineev, S. Mine, R. E. Minvielle, G. Mituka, M. Miura, K. Mizouchi, J. -P. Mols, L. Monfregola, E. Monmarthe, F. Moreau, B. Morgan, S. Moriyama, D. Morris, A. Muir, A. Murakami, J. F. Muratore, M. Murdoch, S. Murphy, J. Myslik, G. Nagashima, T. Nakadaira, M. Nakahata, T. Nakamoto, K. Nakamura, S. Nakayama, T. Nakaya, D. Naples, B. Nelson, T. C. Nicholls, K. Nishikawa, H. Nishino, K. Nitta, F. Nizery, J. A. Nowak, M. Noy, Y. Obayashi, T. Ogitsu, H. Ohhata, T. Okamura, K. Okumura, T. Okusawa, C. Ohlmann, K. Olchanski, R. Openshaw, S. M. Oser, M. Otani, R. A. Owen, Y. Oyama, T. Ozaki, M. Y. Pac, V. Palladino, V. Paolone, P. Paul, D. Payne, G. F. Pearce, C. Pearson, J. D. Perkin, M. Pfleger, F. Pierre, D. Pierrepont, P. Plonski, P. Poffenberger, E. Poplawska, B. Popov, M. Posiadala, J. -M. Poutissou, R. Poutissou, R. Preece, P. Przewlocki, W. Qian, J. L. Raaf, E. Radicioni, K. Ramos, P. Ratoff, T. M. Raufer, M. Ravonel, M. Raymond, F. Retiere, D. Richards, J. -L. Ritou, A. Robert, P. A. Rodrigues, E. Rondio, M. Roney, M. Rooney, D. Ross, B. Rossi, S. Roth, A. Rubbia, D. Ruterbories, R. Sacco, S. Sadler, K. Sakashita, F. Sanchez, A. Sarrat, K. Sasaki, P. Schaack, J. Schmidt, K. Scholberg, J. Schwehr, M. Scott, D. I. Scully, Y. Seiya, T. Sekiguchi, H. Sekiya, G. Sheffer, M. Shibata, Y. Shimizu, M. Shiozawa, S. Short, M. Siyad, D. Smith, R. J. Smith, M. Smy, J. Sobczyk, H. Sobel, S. Sooriyakumaran, M. Sorel, J. Spitz, A. Stahl, P. Stamoulis, O. Star, J. Statter, L. Stawnyczy, J. Steinmann, J. Steffens, B. Still, M. Stodulski, J. Stone, C. Strabel, T. Strauss, R. Sulej, P. Sutcliffe, A. Suzuki, K. Suzuki, S. Suzuki, S. Y. Suzuki, Y. Suzuki, Y. Suzuki, J. Swierblewski, T. Szeglowski, M. Szeptycka, R. Tacik, M. Tada, A. S. Tadepalli, M. Taguchi, S. Takahashi, A. Takeda, Y. Takenaga, Y. Takeuchi, H. A. Tanaka, K. Tanaka, M. Tanaka, M. M. Tanaka, N. Tanimoto, K. Tashiro, I. J. Taylor, A. Terashima, D. Terhorst, R. Terri, L. F. Thompson, A. Thorley, M. Thorpe, W. Toki, T. Tomaru, Y. Totsuka, C. Touramanis, T. Tsukamoto, V. Tvaskis, M. Tzanov, Y. Uchida, K. Ueno, M. Usseglio, A. Vacheret, M. Vagins, J. F. Van Schalkwyk, J. -C. Vanel, G. Vasseur, O. Veledar, P. Vincent, T. Wachala, A. V. Waldron, C. W. Walter, P. J. Wanderer, M. A. Ward, G. P. Ward, D. Wark, D. Warner, M. O. Wascko, A. Weber, R. Wendell, J. Wendland, N. West, L. H. Whitehead, G. Wikström, R. J. Wilkes, M. J. Wilking, Z. Williamson, J. R. Wilson, R. J. Wilson, K. Wong, T. Wongjirad, S. Yamada, Y. Yamada, A. Yamamoto, K. Yamamoto, Y. Yamanoi, H. Yamaoka, C. Yanagisawa, T. Yano, S. Yen, N. Yershov, M. Yokoyama, A. Zalewska, J. Zalipska, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, J. Zmuda
C. Amsler, A. Ariga, T. Ariga, S. Braccini, C. Canali, A. Ereditato, J. Kawada, M. Kimura, I. Kreslo, C. Pistillo, P. Scampoli, J. W. Storey
We propose to build and operate a detector based on the emulsion film technology for the measurement of the gravitational acceleration on antimatter, to be performed by the AEgIS experiment (AD6) at CERN. The goal of AEgIS is to test the weak equivalence principle with a precision of 1% on the gravitational acceleration g by measuring the vertical position of the anni- hilation vertex of antihydrogen atoms after their free fall in a horizontal vacuum pipe. With the emulsion technology developed at the University of Bern we propose to improve the performance of AEgIS by exploiting the superior position resolution of emulsion films over other particle de- tectors. The idea is to use a new type of emulsion films, especially developed for applications in vacuum, to yield a spatial resolution of the order of one micron in the measurement of the sag of the antihydrogen atoms in the gravitational field. This is an order of magnitude better than what was planned in the original AEgIS proposal.
OPERA Collaboration, N. Agafonova, A. Aleksandrov, A. Anokhina, S. Aoki, A. Ariga, T. Ariga, T. Asada, D. Bender, A. Bertolin, C. Bozza, R. Brugnera, A. Buonaura, S. Buontempo, B. Buttne, M. Chernyavsky, A. Chukanov, L. Consiglio, N. D'Ambrosio, G. De Lellis, M. De Serio, P. Del Amo Sanchez, A. Di Crescenzo, D. Di Ferdinando, N. Di Marco, S. Dmitrievski, M. Dracos, D. Duchesneau, S. Dusini, T. Dzhatdoev, J. Ebert, A. Ereditato, R. A. Fini, T. Fukuda, G. Galati, A. Garfagnini, G. Giacomelli, C. Goellnitz, J. Goldberg, Y. Gornushkin, G. Grella, M. Guler, C. Gustavino, C. Hagner, T. Hara, T. Hayakawa, A. Hollnagel, B. Hosseini, H. Ishida, K. Ishiguro, K. Jakovcic, C. Jollet, C. Kamiscioglu, M. Kamiscioglu, T. Katsuragawa, J. Kawada, H. Kawahara, J. H. Kim, S. H. Kim, N. Kitagawa, B. Klicek, K. Kodama, M. Komatsu, U. Kose, I. Kreslo, A. Lauria, J. Lenkeit, A. Ljubicic, A. Longhin, P. Loverre, M. Malenica, A. Malgin, G. Mandrioli, T. Matsuo, V. Matveev, N. Mauri, E. Medinaceli, A. Meregaglia, M. Meyer, S. Mikado, M. Miyanishi, P. Monacelli, M. C. Montesi, K. Morishima, M. T. Muciaccia, N. Naganawa, T. Naka, M. Nakamura, T. Nakano, Y. Nakatsuka, K. Niwa, S. Ogawa, N. Okateva, A. Olshevsky, T. Omura, K. Ozaki, A. Paoloni, B. D. Park, I. G. Park, L. Pasqualini, A. Pastore, L. Patrizii, H. Pessard, C. Pistillo, D. Podgrudkov, N. Polukhina, M. Pozzato, F. Pupilli, M. Roda, T. Roganova, H. Rokujo, G. Rosa, O. Ryazhskaya, O. Sato, A. Schembri, I. Shakiryanova, T. Shchedrina, A. Sheshukov, H. Shibuya, T. Shiraishi, G. Shoziyoev, S. Simone, M. Sioli, C. Sirignano, G. Sirri, M. Spinetti, L. Stanco, N. Starkov, S. M. Stellacci, M. Stipcevic, P. Strolin, S. Takahashi, M. Tenti, F. Terranova, V. Tioukov, S. Tufanli, A. Umemoto, P. Vilain, M. Vladimirov, L. Votano, J. L. Vuilleumier, G. Wilquet, B. Wonsak, C. S. Yoon, I. Yaguchi, M. Yoshimoto, S. Zemskova, A. Zghiche
The OPERA experiment is searching for nu_mu -> nu_tau oscillations in appearance mode i.e. via the direct detection of tau leptons in nu_tau charged current interactions. The evidence of nu_mu -> nu_tau appearance has been previously reported with three nu_tau candidate events using a sub-sample of data from the 2008-2012 runs. We report here a fourth nu_tau candidate event, with the tau decaying into a hadron, found after adding the 2012 run events without any muon in the final state to the data sample. Given the number of analysed events and the low background, nu_mu -> nu_tau oscillations are established with a significance of 4.2sigma.
Philip Ilten, Nhan Tran, Patrick Achenbach, Akitaka Ariga, Tomoko Ariga, Marco Battaglieri, Jianming Bian, Pietro Bisio, Andrea Celentano, Matthew Citron, Paolo Crivelli, Giovanni de Lellis, Antonia Di Crescenzo, Milind Diwan, Jonathan L. Feng, Corrado Gatto, Stefania Gori, Felix Kling, Luca Marsicano, Simone M. Mazza, Josh McFayden, Laura Molina-Bueno, Marco Spreafico, Natalia Toro, Matthew Toups, Sebastian Trojanowski, Yu-Dai Tsai, Mike Williams, Jacob Zettlemoyer, Yiming Zhong
This paper provides an overview of experiments and facilities for accelerator-based dark matter searches as part of the US Community Study on the Future of Particle Physics (Snowmass 2021). Companion white papers to this paper present the physics drivers: thermal dark matter, visible dark portals, and new flavors and rich dark sectors.
Luis A. Anchordoqui, Akitaka Ariga, Tomoko Ariga, Weidong Bai, Kincso Balazs, Brian Batell, Jamie Boyd, Joseph Bramante, Mario Campanelli, Adrian Carmona, Francesco G. Celiberto, Grigorios Chachamis, Matthew Citron, Giovanni De Lellis, Albert De Roeck, Hans Dembinski, Peter B. Denton, Antonia Di Crecsenzo, Milind V. Diwan, Liam Dougherty, Herbi K. Dreiner, Yong Du, Rikard Enberg, Yasaman Farzan, Jonathan L. Feng, Max Fieg, Patrick Foldenauer, Saeid Foroughi-Abari, Alexander Friedland, Michael Fucilla, Jonathan Gall, Maria Vittoria Garzelli, Francesco Giuli, Victor P. Goncalves, Marco Guzzi, Francis Halzen, Juan Carlos Helo, Christopher S. Hill, Ahmed Ismail, Ameen Ismail, Richard Jacobsson, Sudip Jana, Yu Seon Jeong, Krzysztof Jodlowski, Kevin J. Kelly, Felix Kling, Fnu Karan Kumar, Zhen Liu, Rafal Maciula, Roshan Mammen Abraham, Julien Manshanden, Josh McFayden, Mohammed M. A. Mohammed, Pavel M. Nadolsky, Nobuchika Okada, John Osborne, Hidetoshi Otono, Vishvas Pandey, Alessandro Papa, Digesh Raut, Mary Hall Reno, Filippo Resnati, Adam Ritz, Juan Rojo, Ina Sarcevic, Christiane Scherb, Holger Schulz, Pedro Schwaller, Dipan Sengupta, Torbjörn Sjöstrand, Tyler B. Smith, Dennis Soldin, Anna Stasto, Antoni Szczurek, Zahra Tabrizi, Sebastian Trojanowski, Yu-Dai Tsai, Douglas Tuckler, Martin W. Winkler, Keping Xie, Yue Zhang
The Forward Physics Facility (FPF) is a proposal to create a cavern with the space and infrastructure to support a suite of far-forward experiments at the Large Hadron Collider during the High Luminosity era. Located along the beam collision axis and shielded from the interaction point by at least 100 m of concrete and rock, the FPF will house experiments that will detect particles outside the acceptance of the existing large LHC experiments and will observe rare and exotic processes in an extremely low-background environment. In this work, we summarize the current status of plans for the FPF, including recent progress in civil engineering in identifying promising sites for the FPF and the experiments currently envisioned to realize the FPF's physics potential. We then review the many Standard Model and new physics topics that will be advanced by the FPF, including searches for long-lived particles, probes of dark matter and dark sectors, high-statistics studies of TeV neutrinos of all three flavors, aspects of perturbative and non-perturbative QCD, and high-energy astroparticle physics.
FASER Collaboration, Henso Abreu, Elham Amin Mansour, Claire Antel, Akitaka Ariga, Tomoko Ariga, Florian Bernlochner, Tobias Boeckh, Jamie Boyd, Lydia Brenner, Franck Cadoux, David Casper, Charlotte Cavanagh, Xin Chen, Andrea Coccaro, Stephane Debieux, Sergey Dmitrievsky, Monica D'Onofrio, Candan Dozen, Yannick Favre, Deion Fellers, Jonathan L. Feng, Didier Ferrere, Enrico Gamberini, Edward Karl Galantay, Stephen Gibson, Sergio Gonzalez-Sevilla, Yuri Gornushkin, Carl Gwilliam, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Sune Jakobsen, Eliott Johnson, Enrique Kajomovitz, Felix Kling, Umut Kose, Susanne Kuehn, Helena Lefebvre, Lorne Levinson, Ke Li, Jinfeng Liu, Chiara Magliocca, Josh McFayden, Matteo Milanesio, Sam Meehan, Dimitar Mladenov, Theo Moretti, Magdalena Munker, Mitsuhiro Nakamura, Toshiyuki Nakano, Marzio Nessi, Friedemann Neuhaus, Laurie Nevay, Hidetoshi Otono, Carlo Pandini, Hao Pang, Lorenzo Paolozzi, Brian Petersen, Francesco Pietropaolo, Markus Prim, Michaela Queitsch-Maitland, Filippo Resnati, Chiara Rizzi, Elisa Ruiz-Choliz, Hiroki Rokujo, Jakob Salfeld-Nebgen, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Savannah Shively, Roland Sipos, John Spencer, Yosuke Takubo, Noshin Tarannum, Ondrej Theiner, Eric Torrence, Serhan Tufanli, Svetlana Vasina, Benedikt Vormwald, Di Wang
The FASER experiment is a new small and inexpensive experiment that is placed 480 meters downstream of the ATLAS experiment at the CERN LHC. FASER is designed to capture decays of new long-lived particles, produced outside of the ATLAS detector acceptance. These rare particles can decay in the FASER detector together with about 500-1000 Hz of other particles originating from the ATLAS interaction point. A very high efficiency trigger and data acquisition system is required to ensure that the physics events of interest will be recorded. This paper describes the trigger and data acquisition system of the FASER experiment and presents performance results of the system acquired during initial commissioning.
FASER Collaboration, Roshan Mammen Abraham, Xiaocong Ai, Saul Alonso Monsalve, John Anders, Claire Antel, Akitaka Ariga, Tomoko Ariga, Jeremy Atkinson, Florian U. Bernlochner, Tobias Boeckh, Jamie Boyd, Lydia Brenner, Angela Burger, Franck Cadou, Roberto Cardella, David W. Casper, Charlotte Cavanagh, Xin Chen, Kohei Chinone, Dhruv Chouhan, Andrea Coccaro, Stephane Débieu, Ansh Desai, Sergey Dmitrievsky, Radu Dobre, Monica D'Onofrio, Sinead Eley, Yannick Favre, Deion Fellers, 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, Carl Gwilliam, Daiki Hayakawa, Michael Holzbock, 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 Köck, Pantelis Kontaxakis, Umut Kose, Rafaella Kotitsa, Peter Krack, Susanne Kuehn, Thanushan Kugathasan, Lorne Levinson, Botao Li, Jinfeng Liu, Yi Liu, Margaret S. Lutz, Jack MacDonald, Chiara Magliocca, Toni Mäkelä, Lawson McCoy, Josh McFayden, Andrea Pizarro Medina, Matteo Milanesio, Théo Moretti, Keiko Moriyama, Mitsuhiro Nakamura, Toshiyuki Nakano, Laurie Nevay, Motoya Nonaka, Yuma Ohara, Ken Ohashi, Kazuaki Okui, Hidetoshi Otono, Hao Pang, Lorenzo Paolozzi, Pawan Pawan, Brian Petersen, Titi Preda, Markus Prim, Michaela Queitsch-Maitland, Juan Rojo, Hiroki Rokujo, André Rubbia, Jorge Sabater-Iglesias, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Christiano Sebastiani, Anna Sfyrla, Davide Sgalaberna, Mansoora Shamim, Savannah Shively, Yosuke Takubo, Noshin Tarannum, Ondrej Theiner, Simon Thor, Eric Torrence, Oscar Ivan Valdes Martinez, Svetlana Vasina, Benedikt Vormwald, Yuxiao Wang, Eli Welch, Monika Wielers, Benjamin James Wilson, Jialin Wu, Johannes Martin Wuthrich, Yue Xu, Stefano Zambito, Shunliang Zhang, Xingyu Zhao
FASER Collaboration, Roshan Mammen Abraham, Xiaocong Ai, 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, Dhruv Chouhan, Andrea Coccaro, Stephane Débieux, Monica D'Onofrio, Ansh Desai, Sergey Dmitrievsky, Radu Dobre, Sinead Eley, Yannick Favre, Deion Fellers, Jonathan L. Feng, Carlo Alberto Fenoglio, Didier Ferrere, Max Fieg, Wissal Filali, Elena Firu, Edward Galantay, Ali Garabaglu, Stephen Gibson, Sergio Gonzalez-Sevilla, Yuri Gornushkin, Carl Gwilliam, Daiki Hayakawa, Michael Holzbock, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Luca Iodice, Sune Jakobsen, Hans Joos, Enrique Kajomovitz, Hiroaki Kawahara, Alex Keyken, Felix Kling, Daniela Köck, Pantelis Kontaxakis, Umut Kose, Rafaella Kotitsa, Susanne Kuehn, Thanushan Kugathasan, Lorne Levinson, Ke Li, Jinfeng Liu, Yi Liu, Margaret S. Lutz, Jack MacDonald, Chiara Magliocca, Toni Mäkelä, Lawson McCoy, Josh McFayden, Andrea Pizarro Medina, Matteo Milanesio, Théo Moretti, Mitsuhiro Nakamura, Toshiyuki Nakano, Laurie Nevay, Ken Ohashi, Hidetoshi Otono, Hao Pang, Lorenzo Paolozzi, Pawan Pawan, Brian Petersen, Titi Preda, Markus Prim, Michaela Queitsch-Maitland, Hiroki Rokujo, André Rubbia, Jorge Sabater-Iglesias, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Davide Sgalaberna, Mansoora Shamim, Savannah Shively, Yosuke Takubo, Noshin Tarannum, Ondrej Theiner, Eric Torrence, Oscar Ivan Valdes Martinez, Svetlana Vasina, Benedikt Vormwald, Di Wang, Yuxiao Wang, Eli Welch, Monika Wielers, Yue Xu, Samuel Zahorec, Stefano Zambito, Shunliang Zhang
This letter presents the measurement of the energy-dependent neutrino-nucleon cross section in tungsten and the differential flux of muon neutrinos and anti-neutrinos. The analysis is performed using proton-proton collision data at a center-of-mass energy of $13.6 \, {\rm TeV}$ and corresponding to an integrated luminosity of $(65.6 \pm 1.4) \, \mathrm{fb^{-1}}$. Using the active electronic components of the FASER detector, $338.1 \pm 21.0$ charged current muon neutrino interaction events are identified, with backgrounds from other processes subtracted. We unfold the neutrino events into a fiducial volume corresponding to the sensitive regions of the FASER detector and interpret the results in two ways: We use the expected neutrino flux to measure the cross section, and we use the predicted cross section to measure the neutrino flux. Both results are presented in six bins of neutrino energy, achieving the first differential measurement in the TeV range. The observed distributions align with Standard Model predictions. Using this differential data, we extract the contributions of neutrinos from pion and kaon decays.
FASER Collaboration, Henso Abreu, Marco Andreini, Claire Antel, Akitaka Ariga, Tomoko Ariga, Caterina Bertone, Jamie Boyd, Andy Buckley, Franck Cadoux, David W. Casper, Francesco Cerutti, Xin Chen, Andrea Coccaro, Salvatore Danzeca, Liam Dougherty, Candan Dozen, Peter B. Denton, Yannick Favre, Deion Fellers, Jonathan L. Feng, Didier Ferrere, Jonathan Gall, Iftah Galon, Stephen Gibson, Sergio Gonzalez-Sevilla, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Sune Jakobsen, Roland Jansky, Enrique Kajomovitz, Felix Kling, Umut Kose, Susanne Kuehn, Mike Lamont, Helena Lefebvre, Lorne Levinson, Ke Li, Josh McFayden, Sam Meehan, Dimitar Mladenov, Mitsuhiro Nakamura, Toshiyuki Nakano, Marzio Nessi, Friedemann Neuhaus, John Osborne, Hidetoshi Otono, Serge Pelletier, Brian Petersen, Francesco Pietropaolo, Michaela Queitsch-Maitland, Filippo Resnati, Marta Sabate-Gilarte, Jakob Salfeld-Nebgen, Francisco Sanchez Galan, Pablo Santos Diaz, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Holger Schulz, Anna Sfyrla, Savannah Shively, Jordan Smolinsky, Aaron M. Soffa, Yosuke Takubo, Eric Torrence, Sebastian Trojanowski, Serhan Tufanli, Dengfeng Zhang, Gang Zhang
FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest human-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is 25cm x 25cm x 1.35m, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every 20-50 1/fb in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment.
FASER collaboration, Roshan Mammen Abraham, Xiaocong Ai, John Anders, Claire Antel, Akitaka Ariga, Tomoko Ariga, Jeremy Atkinson, Florian U. Bernlochner, Emma Bianchi, Tobias Boeckh, Jamie Boyd, Lydia Brenner, Angela Burger, Franck Cadoux, Roberto Cardella, David W. Casper, Charlotte Cavanagh, Xin Chen, Eunhyung Cho, Dhruv Chouhan, Andrea Coccaro, Stephane Débieux, Monica D'Onofrio, Ansh Desai, Sergey Dmitrievsky, Radu Dobre, Sinead Eley, Yannick Favre, Deion Fellers, Jonathan L. Feng, Carlo Alberto Fenoglio, Didier Ferrere, Max Fieg, Wissal Filali, Elena Firu, Edward Galantay, Ali Garabaglu, Stephen Gibson, Sergio Gonzalez-Sevilla, Yuri Gornushkin, Carl Gwilliam, Daiki Hayakawa, Michael Holzbock, Shih-Chieh Hsu, Zhen Hu, Giuseppe Iacobucci, Tomohiro Inada, Luca Iodice, Sune Jakobsen, Hans Joos, Enrique Kajomovitz, Hiroaki Kawahara, Alex Keyken, Felix Kling, Daniela Köck, Pantelis Kontaxakis, Umut Kose, Rafaella Kotitsa, Susanne Kuehn, Thanushan Kugathasan, Lorne Levinson, Ke Li, Jinfeng Liu, Yi Liu, Margaret S. Lutz, Jack MacDonald, Chiara Magliocca, Toni Mäkelä, Lawson McCoy, Josh McFayden, Andrea Pizarro Medina, Matteo Milanesio, Théo Moretti, Mitsuhiro Nakamura, Toshiyuki Nakano, Laurie Nevay, Ken Ohashi, Hidetoshi Otono, Lorenzo Paolozzi, Brian Petersen, Titi Preda, Markus Prim, Michaela Queitsch-Maitland, Hiroki Rokujo, André Rubbia, Jorge Sabater-Iglesias, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Anna Sfyrla, Davide Sgalaberna, Mansoora Shamim, Savannah Shively, Yosuke Takubo, Noshin Tarannum, Ondrej Theiner, Eric Torrence, Oscar Ivan Valdes Martinez, Svetlana Vasina, Benedikt Vormwald, Di Wang, Yuxiao Wang, Eli Welch, Yue Xu, Samuel Zahorec, Stefano Zambito, Shunliang Zhang
The first FASER search for a light, long-lived particle decaying into a pair of photons is reported. The search uses LHC proton-proton collision data at $\sqrt{s}=13.6~\text{TeV}$ collected in 2022 and 2023, corresponding to an integrated luminosity of $57.7\text{fb}^{-1}$. A model with axion-like particles (ALPs) dominantly coupled to weak gauge bosons is the primary target. Signal events are characterised by high-energy deposits in the electromagnetic calorimeter and no signal in the veto scintillators. One event is observed, compared to a background expectation of $0.44 \pm 0.39$ events, which is entirely dominated by neutrino interactions. World-leading constraints on ALPs are obtained for masses up to $300~\text{MeV}$ and couplings to the Standard Model W gauge boson, $g_{aWW}$, around $10^{-4}$ GeV$^{-1}$, testing a previously unexplored region of parameter space. Other new particle models that lead to the same experimental signature, including ALPs coupled to gluons or photons, U(1)$_B$ gauge bosons, up-philic scalars, and a Type-I two-Higgs doublet model, are also considered for interpretation, and new constraints on previously viable parameter space are presented in this paper.
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, Junkai Qin, Michaela Queitsch-Maitland, Juan Rojo, Hiroki Rokujo, André Rubbia, Osamu Sato, Paola Scampoli, Kristof Schmieden, Matthias Schott, Cristiano Sebastiani, Anna Sfyrla, Davide Sgalaberna, Mansoora Shamim, Yosuke Takubo, Noshin Tarannum, Simon Thor, Eric Torrence, Oscar Ivan Valdes Martinez, Svetlana Vasina, Benedikt Vormwald, Chi Wang, Yuxiao Wang, Eli Welch, Aaron White, Monika Wielers, Benjamin James Wilson, Yue Xu, Heng Yang, Lekai Yao, Daichi Yoshikawa, Stefano Zambito, Shunliang Zhang, Yuxuan Zhang, Xingyu Zhao, Zijian Zhao
Naoto Muto, Hartmut Abele, Tomoko Ariga, Joachim Bosina, Masahiro Hino, Katsuya Hirota, Go Ichikawa, Tobias Jenke, Hiroaki Kawahara, Shinsuke Kawasaki, Masaaki Kitaguchi, Jakob Micko, Kenji Mishima, Naotaka Naganawa, Mitsuhiro Nakamura, Stéphanie Roccia, Osamu Sato, René I. P. Sedmik, Yoshichika Seki, Hirohiko M. Shimizu, Satomi Tada, Atsuhiro Umemoto
Hypothetical short-range interactions could be detected by measuring the wavefunctions of ultracold neutrons (UCNs) on a mirror bounded by the Earth's gravitational field. The Searches require detectors with higher spatial resolution. We are developing a UCN detector for the with a high spatial resolution, which consists of a Si substrate, a thin converter layer including $^{10}$B$_{4}$C, and a layer of fine-grained nuclear emulsion. Its resolution was estimated to be less than 100 nm by fitting tracks of either $^{7}$Li nuclei or $α$-particles, which were created when neutrons interacted with the $^{10}$B$_{4}$C layer. For actual measurements of the spatial distributions, the following two improvements were made: The first was to establish a method to align microscopic images with high accuracy within a wide region of 65 mm $\times$ 0.2 mm. We created reference marks of 1 $μ$m and 5 $μ$m diameter with an interval of 50 $μ$m and 500 $μ$m, respectively, on the Si substrate by electron beam lithography and realized a position accuracy of less than 30 nm. The second was to build a holder that could maintain the atmospheric pressure around the nuclear emulsion to utilize it under vacuum during exposure to UCNs. The intrinsic resolution of the improved detector was estimated by evaluating the blur of a transmission image of a gadolinium grating taken by cold neutrons as better than 0.56 $\pm$ 0.08 $μ$m, which included the grating accuracy. A test exposure to UCNs was conducted to obtain the spatial distribution of UCNs in the Earth's gravitational field. Although the test was successful, a blurring of 6.9 $μ$m was found in the measurements, compared with a theoretical curve. We identified the blurring caused by the refraction of UCNs due to the roughness of the upstream surface of the substrate. Polishing of the surface makes the resolution less than 100 nm.