Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

K Abe; R Akutsu; A Ali; C Alt; C Andreopoulos; L Anthony; M Antonova; S Aoki; A Ariga; Y Asada; Y Ashida; E T Atkin; Y Awataguchi; S Ban; M Barbi; G J Barker; G Barr; D Barrow; C Barry; M Batkiewicz-Kwasniak; A Beloshapkin; F Bench; V Berardi; S Berkman; L Berns; S Bhadra; S Bienstock; A Blondel; S Bolognesi; B Bourguille; S B Boyd; D Brailsford; A Bravar; D Bravo Berguño; C Bronner; A Bubak; M Buizza Avanzini; J Calcutt; T Campbell; S Cao; S L Cartwright; M G Catanesi; A Cervera; A Chappell; C Checchia; D Cherdack; N Chikuma; G Christodoulou; J Coleman; G Collazuol; L Cook; D Coplowe; A Cudd; A Dabrowska; G De Rosa; T Dealtry; P F Denner; S R Dennis; C Densham; F Di Lodovico; N Dokania; S Dolan; T A Doyle; O Drapier; J Dumarchez; P Dunne; L Eklund; S Emery-Schrenk; A Ereditato; P Fernandez; T Feusels; A J Finch; G A Fiorentini; G Fiorillo; C Francois; M Friend; Y Fujii; R Fujita; D Fukuda; R Fukuda; Y Fukuda; K Fusshoeller; K Gameil; C Giganti; T Golan; M Gonin; A Gorin; M Guigue; D R Hadley; J T Haigh; P Hamacher-Baumann; M Hartz; T Hasegawa; N C Hastings; T Hayashino; Y Hayato; A Hiramoto; M Hogan; J Holeczek; N T Hong Van; F Iacob; A K Ichikawa; M Ikeda; T Ishida; T Ishii; M Ishitsuka; K Iwamoto; A Izmaylov; M Jakkapu; B Jamieson; S J Jenkins; C Jesús-Valls; M Jiang; S Johnson; P Jonsson; C K Jung; M Kabirnezhad; A C Kaboth; T Kajita; H Kakuno; J Kameda; D Karlen; S P Kasetti; Y Kataoka; T Katori; Y Kato; E Kearns; M Khabibullin; A Khotjantsev; T Kikawa; H Kim; J Kim; S King; J Kisiel; A Knight; A Knox; T Kobayashi; L Koch; T Koga; A Konaka; L L Kormos; Y Koshio; A Kostin; K Kowalik; H Kubo; Y Kudenko; N Kukita; S Kuribayashi; R Kurjata; T Kutter; M Kuze; L Labarga; J Lagoda; M Lamoureux; M Laveder; M Lawe; M Licciardi; T Lindner; R P Litchfield; S L Liu; X Li; A Longhin; L Ludovici; X Lu; T Lux; L N Machado; L Magaletti; K Mahn; M Malek; S Manly; L Maret; A D Marino; L Marti-Magro; J F Martin; T Maruyama; T Matsubara; K Matsushita; V Matveev; K Mavrokoridis; E Mazzucato; M McCarthy; N McCauley; K S McFarland; C McGrew; A Mefodiev; C Metelko; M Mezzetto; A Minamino; O Mineev; S Mine; M Miura; L Molina Bueno; S Moriyama; J Morrison; Th A Mueller; L Munteanu; S Murphy; Y Nagai; T Nakadaira; M Nakahata; Y Nakajima; A Nakamura; K G Nakamura; K Nakamura; S Nakayama; T Nakaya; K Nakayoshi; C Nantais; T V Ngoc; K Niewczas; K Nishikawa; Y Nishimura; T S Nonnenmacher; F Nova; P Novella; J Nowak; J C Nugent; H M O'Keeffe; L O'Sullivan; T Odagawa; K Okumura; T Okusawa; S M Oser; R A Owen; Y Oyama; V Palladino; J L Palomino; V Paolone; W C Parker; J Pasternak; P Paudyal; M Pavin; D Payne; G C Penn; L Pickering; C Pidcott; G Pintaudi; E S Pinzon Guerra; C Pistillo; B Popov; K Porwit; M Posiadala-Zezula; A Pritchard; B Quilain; T Radermacher; E Radicioni; B Radics; P N Ratoff; E Reinherz-Aronis; C Riccio; E Rondio; S Roth; A Rubbia; A C Ruggeri; C A Ruggles; A Rychter; K Sakashita; F Sánchez; C M Schloesser; K Scholberg; J Schwehr; M Scott; Y Seiya; T Sekiguchi; H Sekiya; D Sgalaberna; R Shah; A Shaikhiev; F Shaker; A Shaykina; M Shiozawa; W Shorrock; A Shvartsman; A Smirnov; M Smy; J T Sobczyk; H Sobel; F J P Soler; Y Sonoda; J Steinmann; S Suvorov; A Suzuki; S Y Suzuki; Y Suzuki; A A Sztuc; M Tada; M Tajima; A Takeda; Y Takeuchi; H K Tanaka; H A Tanaka; S Tanaka; L F Thompson; W Toki; C Touramanis; T Towstego; K M Tsui; T Tsukamoto; M Tzanov; Y Uchida; W Uno; M Vagins; S Valder; Z Vallari; D Vargas; G Vasseur; C Vilela; W G S Vinning; T Vladisavljevic; V V Volkov; T Wachala; J Walker; J G Walsh; Y Wang; D Wark; M O Wascko; A Weber; R Wendell; M J Wilking; C Wilkinson; J R Wilson; R J Wilson; K Wood; C Wret; Y Yamada; K Yamamoto; C Yanagisawa; G Yang; T Yano; K Yasutome; S Yen; N Yershov; M Yokoyama; T Yoshida; M Yu; A Zalewska; J Zalipska; K Zaremba; G Zarnecki; M Ziembicki; E D Zimmerman; M Zito; S Zsoldos; A Zykova; T2K Collaboration

doi:10.1103/PhysRevLett.124.161802

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Phys Rev Lett. 2020 Apr 24;124(16):161802. doi: 10.1103/PhysRevLett.124.161802.

Authors

K Abe¹, R Akutsu², A Ali³, C Alt⁴, C Andreopoulos^{5

6}, L Anthony⁵, M Antonova⁷, S Aoki⁸, A Ariga⁹, Y Asada¹⁰, Y Ashida³, E T Atkin¹¹, Y Awataguchi¹², S Ban³, M Barbi¹³, G J Barker¹⁴, G Barr¹⁵, D Barrow¹⁵, C Barry⁵, M Batkiewicz-Kwasniak¹⁶, A Beloshapkin¹⁷, F Bench⁵, V Berardi¹⁸, S Berkman^{19

20}, L Berns²¹, S Bhadra²², S Bienstock²³, A Blondel^{24

23}, S Bolognesi²⁵, B Bourguille²⁶, S B Boyd¹⁴, D Brailsford²⁷, A Bravar²⁴, D Bravo Berguño²⁸, C Bronner¹, A Bubak²⁹, M Buizza Avanzini³⁰, J Calcutt³¹, T Campbell³², S Cao³³, S L Cartwright³⁴, M G Catanesi¹⁸, A Cervera⁷, A Chappell¹⁴, C Checchia³⁵, D Cherdack³⁶, N Chikuma³⁷, G Christodoulou³⁸, J Coleman⁵, G Collazuol³⁵, L Cook^{39

15}, D Coplowe¹⁵, A Cudd³¹, A Dabrowska¹⁶, G De Rosa⁴⁰, T Dealtry²⁷, P F Denner¹⁴, S R Dennis⁵, C Densham⁶, F Di Lodovico⁴¹, N Dokania⁴², S Dolan³⁸, T A Doyle²⁷, O Drapier³⁰, J Dumarchez²³, P Dunne¹¹, L Eklund⁴³, S Emery-Schrenk²⁵, A Ereditato⁹, P Fernandez⁷, T Feusels^{19

20}, A J Finch²⁷, G A Fiorentini²², G Fiorillo⁴⁰, C Francois⁹, M Friend³³, Y Fujii³³, R Fujita³⁷, D Fukuda⁴⁴, R Fukuda⁴⁵, Y Fukuda⁴⁶, K Fusshoeller⁴, K Gameil^{19

20}, C Giganti²³, T Golan⁴⁷, M Gonin³⁰, A Gorin¹⁷, M Guigue²³, D R Hadley¹⁴, J T Haigh¹⁴, P Hamacher-Baumann⁴⁸, M Hartz^{39

20}, T Hasegawa³³, N C Hastings³³, T Hayashino³, Y Hayato^{39

1}, A Hiramoto³, M Hogan⁴⁹, J Holeczek²⁹, N T Hong Van^{50

51}, F Iacob³⁵, A K Ichikawa³, M Ikeda¹, T Ishida³³, T Ishii³³, M Ishitsuka⁴⁵, K Iwamoto³⁷, A Izmaylov^{7

17}, M Jakkapu³³, B Jamieson⁵², S J Jenkins³⁴, C Jesús-Valls²⁶, M Jiang³, S Johnson³², P Jonsson¹¹, C K Jung⁴², M Kabirnezhad¹⁵, A C Kaboth^{53

6}, T Kajita², H Kakuno¹², J Kameda¹, D Karlen^{20

54}, S P Kasetti⁵⁵, Y Kataoka¹, T Katori⁴¹, Y Kato¹, E Kearns^{56

39}, M Khabibullin¹⁷, A Khotjantsev¹⁷, T Kikawa³, H Kim⁵⁷, J Kim^{19

20}, S King⁵⁸, J Kisiel²⁹, A Knight¹⁴, A Knox²⁷, T Kobayashi³³, L Koch¹⁵, T Koga³⁷, A Konaka²⁰, L L Kormos²⁷, Y Koshio⁴⁴, A Kostin¹⁷, K Kowalik⁵⁹, H Kubo³, Y Kudenko¹⁷, N Kukita⁵⁷, S Kuribayashi³, R Kurjata⁶⁰, T Kutter⁵⁵, M Kuze²¹, L Labarga²⁸, J Lagoda⁵⁹, M Lamoureux³⁵, M Laveder³⁵, M Lawe²⁷, M Licciardi³⁰, T Lindner²⁰, R P Litchfield⁴³, S L Liu⁴², X Li⁴², A Longhin³⁵, L Ludovici⁶¹, X Lu¹⁵, T Lux²⁶, L N Machado⁴⁰, L Magaletti¹⁸, K Mahn³¹, M Malek³⁴, S Manly⁶², L Maret²⁴, A D Marino³², L Marti-Magro^{39

1}, J F Martin⁶³, T Maruyama³³, T Matsubara³³, K Matsushita³⁷, V Matveev¹⁷, K Mavrokoridis⁵, E Mazzucato²⁵, M McCarthy²², N McCauley⁵, K S McFarland⁶², C McGrew⁴², A Mefodiev¹⁷, C Metelko⁵, M Mezzetto³⁵, A Minamino¹⁰, O Mineev¹⁷, S Mine⁶⁴, M Miura¹, L Molina Bueno⁴, S Moriyama¹, J Morrison³¹, Th A Mueller³⁰, L Munteanu²⁵, S Murphy⁴, Y Nagai³², T Nakadaira³³, M Nakahata^{39

1}, Y Nakajima¹, A Nakamura⁴⁴, K G Nakamura³, K Nakamura^{33

39}, S Nakayama^{39

1}, T Nakaya^{39

3}, K Nakayoshi³³, C Nantais⁶³, T V Ngoc⁵⁰, K Niewczas⁴⁷, K Nishikawa³³, Y Nishimura⁶⁵, T S Nonnenmacher¹¹, F Nova⁶, P Novella⁷, J Nowak²⁷, J C Nugent⁴³, H M O'Keeffe²⁷, L O'Sullivan³⁴, T Odagawa³, K Okumura^{39

2}, T Okusawa⁵⁷, S M Oser^{19

20}, R A Owen⁵⁸, Y Oyama³³, V Palladino⁴⁰, J L Palomino⁴², V Paolone⁶⁶, W C Parker⁵³, J Pasternak¹¹, P Paudyal⁵, M Pavin²⁰, D Payne⁵, G C Penn⁵, L Pickering³¹, C Pidcott³⁴, G Pintaudi¹⁰, E S Pinzon Guerra²², C Pistillo⁹, B Popov²³, K Porwit²⁹, M Posiadala-Zezula⁶⁷, A Pritchard⁵, B Quilain³⁹, T Radermacher⁴⁸, E Radicioni¹⁸, B Radics⁴, P N Ratoff²⁷, E Reinherz-Aronis⁴⁹, C Riccio⁴⁰, E Rondio⁵⁹, S Roth⁴⁸, A Rubbia⁴, A C Ruggeri⁴⁰, C A Ruggles⁴³, A Rychter⁶⁰, K Sakashita³³, F Sánchez²⁴, C M Schloesser⁴, K Scholberg⁶⁸, J Schwehr⁴⁹, M Scott¹¹, Y Seiya⁵⁷, T Sekiguchi³³, H Sekiya^{39

1}, D Sgalaberna³⁸, R Shah^{15

6}, A Shaikhiev¹⁷, F Shaker⁵², A Shaykina¹⁷, M Shiozawa^{39

1}, W Shorrock¹¹, A Shvartsman¹⁷, A Smirnov¹⁷, M Smy⁶⁴, J T Sobczyk⁴⁷, H Sobel^{64

39}, F J P Soler⁴³, Y Sonoda¹, J Steinmann⁴⁸, S Suvorov^{25

17}, A Suzuki⁸, S Y Suzuki³³, Y Suzuki³⁹, A A Sztuc¹¹, M Tada³³, M Tajima³, A Takeda¹, Y Takeuchi^{39

8}, H K Tanaka¹, H A Tanaka^{69

63}, S Tanaka⁵⁷, L F Thompson³⁴, W Toki⁴⁹, C Touramanis⁵, T Towstego⁶³, K M Tsui⁵, T Tsukamoto³³, M Tzanov⁵⁵, Y Uchida¹¹, W Uno³, M Vagins^{64

39}, S Valder¹⁴, Z Vallari⁴², D Vargas²⁶, G Vasseur²⁵, C Vilela⁴², W G S Vinning¹⁴, T Vladisavljevic^{39

15}, V V Volkov¹⁷, T Wachala¹⁶, J Walker⁵², J G Walsh²⁷, Y Wang⁴², D Wark^{15

6}, M O Wascko¹¹, A Weber^{15

6}, R Wendell³, M J Wilking⁴², C Wilkinson⁹, J R Wilson⁴¹, R J Wilson⁴⁹, K Wood⁴², C Wret⁶², Y Yamada³³, K Yamamoto⁵⁷, C Yanagisawa⁴², G Yang⁴², T Yano¹, K Yasutome³, S Yen²⁰, N Yershov¹⁷, M Yokoyama³⁷, T Yoshida²¹, M Yu²², A Zalewska¹⁶, J Zalipska⁵⁹, K Zaremba⁶⁰, G Zarnecki⁵⁹, M Ziembicki⁶⁰, E D Zimmerman³², M Zito²³, S Zsoldos⁵⁸, A Zykova¹⁷; T2K Collaboration

Affiliations

¹ University of Tokyo, Institute for Cosmic Ray Research, Kamioka Observatory, Kamioka, Japan.
² University of Tokyo, Institute for Cosmic Ray Research, Research Center for Cosmic Neutrinos, Kashiwa, Japan.
³ Kyoto University, Department of Physics, Kyoto, Japan.
⁴ ETH Zurich, Institute for Particle Physics and Astrophysics, Zurich, Switzerland.
⁵ University of Liverpool, Department of Physics, Liverpool, United Kingdom.
⁶ STFC, Rutherford Appleton Laboratory, Harwell Oxford, and Daresbury Laboratory, Warrington, United Kingdom.
⁷ IFIC (CSIC & University of Valencia), Valencia, Spain.
⁸ Kobe University, Kobe, Japan.
⁹ University of Bern, Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), Bern, Switzerland.
¹⁰ Yokohama National University, Faculty of Engineering, Yokohama, Japan.
¹¹ Imperial College London, Department of Physics, London, United Kingdom.
¹² Tokyo Metropolitan University, Department of Physics, Tokyo, Japan.
¹³ University of Regina, Department of Physics, Regina, Saskatchewan, Canada.
¹⁴ University of Warwick, Department of Physics, Coventry, United Kingdom.
¹⁵ Oxford University, Department of Physics, Oxford, United Kingdom.
¹⁶ H. Niewodniczanski Institute of Nuclear Physics PAN, Cracow, Poland.
¹⁷ Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia.
¹⁸ INFN Sezione di Bari and Università e Politecnico di Bari, Dipartimento Interuniversitario di Fisica, Bari, Italy.
¹⁹ University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia, Canada.
²⁰ TRIUMF, Vancouver, British Columbia, Canada.
²¹ Tokyo Institute of Technology, Department of Physics, Tokyo, Japan.
²² York University, Department of Physics and Astronomy, Toronto, Ontario, Canada.
²³ Sorbonne Université, Université Paris Diderot, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE), Paris, France.
²⁴ University of Geneva, Section de Physique, DPNC, Geneva, Switzerland.
²⁵ IRFU, CEA Saclay, Gif-sur-Yvette, France.
²⁶ Institut de Fisica d'Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra (Barcelona) Spain.
²⁷ Lancaster University, Physics Department, Lancaster, United Kingdom.
²⁸ University Autonoma Madrid, Department of Theoretical Physics, Madrid, Spain.
²⁹ University of Silesia, Institute of Physics, Katowice, Poland.
³⁰ Ecole Polytechnique, IN2P3-CNRS, Laboratoire Leprince-Ringuet, Palaiseau, France.
³¹ Michigan State University, Department of Physics and Astronomy, East Lansing, Michigan, USA.
³² University of Colorado at Boulder, Department of Physics, Boulder, Colorado, USA.
³³ High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan.
³⁴ University of Sheffield, Department of Physics and Astronomy, Sheffield, United Kingdom.
³⁵ INFN Sezione di Padova and Università di Padova, Dipartimento di Fisica, Padova, Italy.
³⁶ University of Houston, Department of Physics, Houston, Texas, USA.
³⁷ University of Tokyo, Department of Physics, Tokyo, Japan.
³⁸ CERN European Organization for Nuclear Research, CH-1211 Genève 23, Switzerland.
³⁹ Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, University of Tokyo, Kashiwa, Chiba, Japan.
⁴⁰ INFN Sezione di Napoli and Università di Napoli, Dipartimento di Fisica, Napoli, Italy.
⁴¹ King's College London, Department of Physics, Strand, London WC2R 2LS, United Kingdom.
⁴² State University of New York at Stony Brook, Department of Physics and Astronomy, Stony Brook, New York, USA.
⁴³ University of Glasgow, School of Physics and Astronomy, Glasgow, United Kingdom.
⁴⁴ Okayama University, Department of Physics, Okayama, Japan.
⁴⁵ Tokyo University of Science, Faculty of Science and Technology, Department of Physics, Noda, Chiba, Japan.
⁴⁶ Miyagi University of Education, Department of Physics, Sendai, Japan.
⁴⁷ Wroclaw University, Faculty of Physics and Astronomy, Wroclaw, Poland.
⁴⁸ RWTH Aachen University, III. Physikalisches Institut, Aachen, Germany.
⁴⁹ Colorado State University, Department of Physics, Fort Collins, Colorado, USA.
⁵⁰ Institute For Interdisciplinary Research in Science and Education (IFIRSE), ICISE, Quy Nhon, Vietnam.
⁵¹ International Centre of Physics, Institute of Physics (IOP), Vietnam Academy of Science and Technology (VAST), 10 Dao Tan, Ba Dinh, Hanoi, Vietnam.
⁵² University of Winnipeg, Department of Physics, Winnipeg, Manitoba, Canada.
⁵³ Royal Holloway University of London, Department of Physics, Egham, Surrey, United Kingdom.
⁵⁴ University of Victoria, Department of Physics and Astronomy, Victoria, British Columbia, Canada.
⁵⁵ Louisiana State University, Department of Physics and Astronomy, Baton Rouge, Louisiana, USA.
⁵⁶ Boston University, Department of Physics, Boston, Massachusetts, USA.
⁵⁷ Osaka City University, Department of Physics, Osaka, Japan.
⁵⁸ Queen Mary University of London, School of Physics and Astronomy, London, United Kingdom.
⁵⁹ National Centre for Nuclear Research, Warsaw, Poland.
⁶⁰ Warsaw University of Technology, Institute of Radioelectronics and Multimedia Technology, Warsaw, Poland.
⁶¹ INFN Sezione di Roma and Università di Roma "La Sapienza", Roma, Italy.
⁶² University of Rochester, Department of Physics and Astronomy, Rochester, New York, USA.
⁶³ University of Toronto, Department of Physics, Toronto, Ontario, Canada.
⁶⁴ University of California, Irvine, Department of Physics and Astronomy, Irvine, California, USA.
⁶⁵ Keio University, Department of Physics, Kanagawa, Japan.
⁶⁶ University of Pittsburgh, Department of Physics and Astronomy, Pittsburgh, Pennsylvania, USA.
⁶⁷ University of Warsaw, Faculty of Physics, Warsaw, Poland.
⁶⁸ Duke University, Department of Physics, Durham, North Carolina, USA.
⁶⁹ SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA.

PMID: 32383902
DOI: 10.1103/PhysRevLett.124.161802

Abstract

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.