Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector
We present the results of the charge ratio (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>R</a:mi></a:math>) and polarization (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msubsup><c:mi>P</c:mi><c:mn>0</c:mn><c:mi>μ</c:mi></c:msubsup></c:math>) measurements using decay electron events collected between September 2008 and June 2022 with the Super-Kamiokande detector. Because of its underground location and long operation, we are able to perform high-precision measurements by accumulating cosmic-ray muons. We measured the muon charge ratio to be <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>R</e:mi><e:mo>=</e:mo><e:mn>1.32</e:mn><e:mo>±</e:mo><e:mn>0.02</e:mn><e:mo stretchy="false">(</e:mo><e:mrow><e:mi>stat</e:mi></e:mrow><e:mo>+</e:mo><e:mrow><e:mi>syst</e:mi></e:mrow><e:mo stretchy="false">)</e:mo></e:math> at <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>E</i:mi><i:mi>μ</i:mi></i:msub><i:mi>cos</i:mi><i:msub><i:mi>θ</i:mi><i:mtext>Zenith</i:mtext></i:msub><i:mo>=</i:mo><i:msubsup><i:mn>0.7</i:mn><i:mrow><i:mo>−</i:mo><i:mn>0.2</i:mn></i:mrow><i:mrow><i:mo>+</i:mo><i:mn>0.3</i:mn></i:mrow></i:msubsup><i:mtext> </i:mtext><i:mtext> </i:mtext><i:mi>TeV</i:mi></i:math>, where <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msub><k:mi>E</k:mi><k:mi>μ</k:mi></k:msub></k:math> is the muon energy and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:msub><m:mi>θ</m:mi><m:mtext>Zenith</m:mtext></m:msub></m:math> is the zenith angle of incoming cosmic-ray muons. This result is consistent with the Honda flux model while indicating a tension with the <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mi>π</o:mi><o:mi>K</o:mi></o:math> model of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mn>1.9</q:mn><q:mi>σ</q:mi></q:math>. We also measured the muon polarization at the production location to be <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mrow><s:msubsup><s:mrow><s:mi>P</s:mi></s:mrow><s:mrow><s:mn>0</s:mn></s:mrow><s:mrow><s:mi>μ</s:mi></s:mrow></s:msubsup><s:mo>=</s:mo><s:mn>0.52</s:mn><s:mo>±</s:mo><s:mn>0.02</s:mn><s:mtext> </s:mtext><s:mtext> </s:mtext><s:mo stretchy="false">(</s:mo><s:mrow><s:mi>stat</s:mi></s:mrow><s:mo>+</s:mo><s:mrow><s:mi>syst</s:mi></s:mrow><s:mo stretchy="false">)</s:mo></s:mrow></s:math> at the muon momentum of <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:msubsup><w:mn>0.9</w:mn><w:mrow><w:mo>−</w:mo><w:mn>0.1</w:mn></w:mrow><w:mrow><w:mo>+</w:mo><w:mn>0.6</w:mn></w:mrow></w:msubsup><w:mtext> </w:mtext><w:mtext> </w:mtext><w:mi>TeV</w:mi><w:mo>/</w:mo><w:mi>c</w:mi></w:math> at the surface of the mountain; this also suggests a tension with the Honda flux model of <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:mn>1.5</y:mn><y:mi>σ</y:mi></y:math>. This is the most precise measurement ever to experimentally determine the cosmic-ray muon polarization near <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mn>1</ab:mn><ab:mtext> </ab:mtext><ab:mtext> </ab:mtext><ab:mi>TeV</ab:mi><ab:mo>/</ab:mo><ab:mi>c</ab:mi></ab:math>. These measurement results are useful to improve atmospheric neutrino simulations. Published by the American Physical Society 2024
Authors
- C. W. Walter (ORCID: https://orcid.org/0000-0003-2035-2380)
- H. W. Sobel (ORCID: https://orcid.org/0000-0001-5073-4043)
- R. Kaneshima
- M. R. Vagins (ORCID: https://orcid.org/0000-0002-0569-0480)
- K. Martens (ORCID: https://orcid.org/0000-0002-5049-3339)
- K. Nishijima (ORCID: https://orcid.org/0000-0002-1830-4251)
- T. Ishizuka
- K. Ieki (ORCID: https://orcid.org/0000-0002-7791-5044)
- M. Lamoureux (ORCID: https://orcid.org/0000-0002-8860-5826)
- L. Ludovici (ORCID: https://orcid.org/0000-0003-1970-9960)
- T. Kinoshita
- S. Moriyama (ORCID: https://orcid.org/0000-0001-7630-2839)
- Y. Hino (ORCID: https://orcid.org/0000-0002-7480-463X)
- D. Barrow (ORCID: https://orcid.org/0000-0001-5844-709X)
- K. Choi (ORCID: https://orcid.org/0000-0002-0932-9123)
- Y. Itow (ORCID: https://orcid.org/0000-0002-8198-1968)
- M. Mori
- K. Wada
- J. L. Raaf (ORCID: https://orcid.org/0000-0002-4533-929X)
- M. Ikeda (ORCID: https://orcid.org/0000-0002-4177-5828)
- D. Marin
- M. Scott (ORCID: https://orcid.org/0000-0002-1759-4453)
- S. Shima
- D. Hadley
- T. Nakadaira
- X. Li
- Lorenzo Périssé (ORCID: https://orcid.org/0000-0003-3444-4454)
- Y. Hayato (ORCID: https://orcid.org/0000-0002-8683-5038)
- F Nakanishi (ORCID: https://orcid.org/0000-0003-4408-6929)
- Z. Hu (ORCID: https://orcid.org/0000-0002-0353-8792)
- T. Suganuma
- S. Suzuki
- L. Kneale (ORCID: https://orcid.org/0000-0002-4087-1244)
- J. Łagoda (ORCID: https://orcid.org/0000-0001-8828-6100)
- H. Menjo (ORCID: https://orcid.org/0000-0001-8466-1938)
- G. Barr (ORCID: https://orcid.org/0000-0002-9763-1882)
- H. Zhong (ORCID: https://orcid.org/0000-0001-8324-5158)
- M. Nicholson
- A. Ali
- S. Yoshida (ORCID: https://orcid.org/0000-0003-2480-5105)
- R. Matsumoto (ORCID: https://orcid.org/0000-0002-4995-9242)
- K. Okumura (ORCID: https://orcid.org/0000-0002-5523-2808)
- A. Yankelevich (ORCID: https://orcid.org/0000-0002-5963-3123)
- M. Shinoki (ORCID: https://orcid.org/0000-0002-9486-6256)
- Th. A. Mueller (ORCID: https://orcid.org/0000-0003-2743-4741)
- T. Nakamura
- K. Shimizu
- Y. Maekawa
- H. Sekiya (ORCID: https://orcid.org/0000-0001-9034-0436)
- H. Shiba
- Y. Noguchi (ORCID: https://orcid.org/0000-0002-3113-3127)
- M Kawaue
- K. Nakamura (ORCID: https://orcid.org/0000-0003-3302-7325)
- Y. Kanemura
- H. Okazawa
- S. B. Kim
- M. D. Thiesse (ORCID: https://orcid.org/0000-0002-0775-250X)
- A. Tarrant (ORCID: https://orcid.org/0000-0002-8750-4759)
- Poonam Mehta (ORCID: https://orcid.org/0000-0001-9829-0517)
- G. T. Burton
- Yusuke Takagi (ORCID: https://orcid.org/0000-0002-0305-1597)
- S. Locke (ORCID: https://orcid.org/0000-0001-9400-5977)
- R. Rogly (ORCID: https://orcid.org/0000-0003-2530-5217)
- Benda Xu (ORCID: https://orcid.org/0000-0001-5135-1319)
- B. Bodur (ORCID: https://orcid.org/0000-0001-8454-271X)
- A. Giampaolo (ORCID: https://orcid.org/0000-0003-4273-6617)
- M. Mattiazzi (ORCID: https://orcid.org/0000-0003-3900-6816)
- S. Watanabe
- J. S. Jang (ORCID: https://orcid.org/0000-0002-8466-0502)
- Y. Ommura
- F. Nova (ORCID: https://orcid.org/0000-0002-0769-9921)
- Y. Oyama (ORCID: https://orcid.org/0000-0002-1689-0285)
- A. K. Ichikawa
- K. Hiraide (ORCID: https://orcid.org/0000-0003-1229-9452)
- T. Nakaya (ORCID: https://orcid.org/0000-0003-3040-4674)
- R. Akutsu
- J. Yang (ORCID: https://orcid.org/0000-0002-3624-3659)
- B. Zaldivar
- B. S. Yang (ORCID: https://orcid.org/0000-0001-5877-6096)
- N. Taniuchi
- T Tada (ORCID: https://orcid.org/0009-0008-8933-0861)
- Jun Hu (ORCID: https://orcid.org/0000-0003-2149-9691)
- Eiichiro Watanabe (ORCID: https://orcid.org/0000-0003-2050-3740)
- K. Hosokawa (ORCID: https://orcid.org/0000-0002-8766-3629)
- J. Yoo (ORCID: https://orcid.org/0000-0002-3826-1332)
- Y. Koshio (ORCID: https://orcid.org/0000-0003-0437-8505)
- T. Tashiro (ORCID: https://orcid.org/0000-0003-1440-3049)
- M. Nakahata (ORCID: https://orcid.org/0000-0001-7783-9080)
- C. K. Jung (ORCID: https://orcid.org/0000-0001-6877-6874)
- E. Kwon (ORCID: https://orcid.org/0000-0001-5653-2880)
- A. Holin
- A. Minamino (ORCID: https://orcid.org/0000-0001-6510-7106)
- L. Wan (ORCID: https://orcid.org/0000-0001-5524-6137)
- H. Ishino
- L.F. Thompson (ORCID: https://orcid.org/0000-0001-6911-4776)
- S. Nakayama (ORCID: https://orcid.org/0000-0002-9145-714X)
- R. G. Park
- S. Sakai (ORCID: https://orcid.org/0000-0002-2190-0062)
- S. Zsoldos (ORCID: https://orcid.org/0000-0003-0142-4844)
- Ll. Marti (ORCID: https://orcid.org/0000-0002-5172-9796)
- S. Izumiyama (ORCID: https://orcid.org/0000-0002-0808-8022)
- K. Abe (ORCID: https://orcid.org/0000-0002-0876-8319)
- A. A. Sztuc (ORCID: https://orcid.org/0000-0001-7679-3455)
- Pascal Paganini (ORCID: https://orcid.org/0000-0001-9580-683X)
- C. Bronner (ORCID: https://orcid.org/0000-0001-9555-6033)
- L. N. Machado (ORCID: https://orcid.org/0000-0002-7578-4183)
- G. Pronost (ORCID: https://orcid.org/0000-0001-6429-5387)
- F. Iacob (ORCID: https://orcid.org/0000-0003-3582-3819)
- Wei Shi (ORCID: https://orcid.org/0000-0001-6130-1227)
- J. M. McElwee (ORCID: https://orcid.org/0000-0001-6841-999X)
- T. Yano (ORCID: https://orcid.org/0000-0002-5320-1709)
- N. Iovine (ORCID: https://orcid.org/0000-0001-7965-2252)
- X. Wang
- T. Katori (ORCID: https://orcid.org/0000-0002-9429-9482)
- V. Berardi (ORCID: https://orcid.org/0000-0002-8387-4568)
- T. Hasegawa (ORCID: https://orcid.org/0000-0002-2967-1954)
- Junfeng Feng (ORCID: https://orcid.org/0000-0001-8981-4489)
- Y. Nakano (ORCID: https://orcid.org/0000-0003-1572-3888)
- M. Kuze (ORCID: https://orcid.org/0000-0001-8858-8440)
- Y. Takeuchi (ORCID: https://orcid.org/0000-0002-4665-2210)
- M. O’Flaherty (ORCID: https://orcid.org/0000-0002-8038-503X)
- N. Shigeta
- P. de Perio (ORCID: https://orcid.org/0000-0002-0741-4471)
- Y. Satou (ORCID: https://orcid.org/0000-0003-3627-0435)
- R. Okazaki (ORCID: https://orcid.org/0000-0002-9792-8870)
- I. Yu (ORCID: https://orcid.org/0000-0003-1567-5548)
- S. Miki
- N. J. Griskevich (ORCID: https://orcid.org/0000-0003-4409-3184)
- T. Ishida
- Y. S. Prabhu
- J. Xia (ORCID: https://orcid.org/0000-0003-1412-092X)
- V. Gousy-Leblanc
- M. Jia (ORCID: https://orcid.org/0009-0002-1191-4660)
- T. Tsukamoto (ORCID: https://orcid.org/0000-0003-1600-6303)
- H. Kitagawa
- N. F. Calabria (ORCID: https://orcid.org/0000-0003-3590-2808)
- H. Ozaki
- S. Sano
- L. H. V. Anthony
- K. Terada
- T. Wester (ORCID: https://orcid.org/0000-0001-6668-7595)
- K. Scholberg (ORCID: https://orcid.org/0000-0002-7007-2021)
- A. Beauchêne
- S. Samani
- G. D. Megias (ORCID: https://orcid.org/0000-0002-0890-1343)
- S. Cao (ORCID: https://orcid.org/0000-0002-9046-5324)
- K. Nakagiri (ORCID: https://orcid.org/0000-0001-8393-1289)
- J. Jiang
- E. Kearns (ORCID: https://orcid.org/0000-0002-1781-150X)
- A. Konaka (ORCID: https://orcid.org/0000-0002-0034-9195)
- Hiroshi Itô (ORCID: https://orcid.org/0000-0003-1029-5730)
- J. Migenda (ORCID: https://orcid.org/0000-0002-5350-8049)
- R. M. Ramsden (ORCID: https://orcid.org/0009-0005-3298-6593)
- K. Ninomiya
- B. Zhang
- Y. Kotsar
- Y. Takemoto (ORCID: https://orcid.org/0000-0003-2232-7277)
- G. Pintaudi (ORCID: https://orcid.org/0000-0002-6363-9712)
- S. M. Lakshmi (ORCID: https://orcid.org/0000-0001-6494-632X)
- M Mandal
- Masayuki Harada (ORCID: https://orcid.org/0000-0003-3273-946X)
- R. A. Wendell (ORCID: https://orcid.org/0000-0002-0969-4681)
- R. Gaur
- J. Bian
- S. Han (ORCID: https://orcid.org/0009-0002-8908-6922)
- Y. Suzuki (ORCID: https://orcid.org/0000-0001-9985-5284)
- S. T. Wilson
- M. B. Smy (ORCID: https://orcid.org/0000-0002-8140-4319)
- C. Jesús-Valls (ORCID: https://orcid.org/0000-0002-0154-2456)
- J. Gao (ORCID: https://orcid.org/0000-0001-9999-9747)
- A. Eguchi (ORCID: https://orcid.org/0000-0002-7753-8656)
- A. Langella (ORCID: https://orcid.org/0000-0001-6273-3558)
- S. Jung (ORCID: https://orcid.org/0009-0007-8244-8106)
- Y. Suzuki (ORCID: https://orcid.org/0000-0001-7340-6675)
- Shaomin Chen (ORCID: https://orcid.org/0000-0002-2376-8413)
- G. Collazuol (ORCID: https://orcid.org/0000-0002-7876-6124)
- B. W. Pointon (ORCID: https://orcid.org/0000-0003-0312-4044)
- S. J. Jenkins (ORCID: https://orcid.org/0000-0002-0982-8141)
- N. Ospina (ORCID: https://orcid.org/0000-0002-8404-1808)
- F. Di Lodovico (ORCID: https://orcid.org/0000-0003-3952-2175)
- J. W. Seo (ORCID: https://orcid.org/0000-0002-2719-2079)
- M. Yokoyama (ORCID: https://orcid.org/0000-0003-2742-0251)
- Yumiko Yoshioka (ORCID: https://orcid.org/0000-0002-4654-0585)
- Y. Nakajima (ORCID: https://orcid.org/0000-0002-2744-5216)
- M. Shiozawa (ORCID: https://orcid.org/0000-0003-0520-3520)
- Z. Xie (ORCID: https://orcid.org/0009-0003-0144-2871)
- M. Miura
- V.V. Tereshchenko
- Y. Kataoka (ORCID: https://orcid.org/0000-0001-9090-4801)
- L. Cook
- M. Jakkapu
- N. McCauley (ORCID: https://orcid.org/0000-0002-5982-5125)
- Y. Fukuda (ORCID: https://orcid.org/0000-0003-2660-1958)
- J. Hill
- Y. Uchida
- P. Fernández (ORCID: https://orcid.org/0000-0001-9034-1930)
- M. Gonin
- T. Kajita
- J. F. Martin
- N. W. Prouse (ORCID: https://orcid.org/0000-0003-1037-3081)
- K. Sakashita
- T. Sekiguchi
- D. Wark
- M. Posiadała-Zezula (ORCID: https://orcid.org/0000-0002-5154-5348)
- T. Kobayashi
- D. H. Moon
- J. Zalipska (ORCID: https://orcid.org/0000-0003-1763-7959)
- H. Tanaka
- C. Yanagisawa (ORCID: https://orcid.org/0000-0002-6490-1743)
- O. Drapier
- S. H. Lee
- A. Takenaka
- L. Labarga (ORCID: https://orcid.org/0000-0002-6395-9142)
- M. Hartz
- Y. Nishimura (ORCID: https://orcid.org/0000-0002-7666-3789)
- P. Mijakowski
- L. Feng (ORCID: https://orcid.org/0009-0005-1768-7755)
- A. De Souza Santos
- S. B. Boyd
- B. Jamieson
- S. J. Jenkins (ORCID: https://orcid.org/0000-0002-0982-8141)
- J. Kameda
- E. Radicioni
- K. M. Tsui
- G. De Rosa
- M. Friend
- T. Yoshida
- B. Quilain
- A. Goldsack
- T. Kikawa
- R. Edwards
- M. G. Catanesi
- J. G. Learned
- T. Towstego
- B. Richards
- S. Tairafune
- M. Ishitsuka
- Y. Kashiwagi
- S. Amanai
- M. J. Wilking
- T. Tano
- S. Mine
- Tomoaki Tomiya
- S. Fujita (ORCID: https://orcid.org/0000-0002-0281-2243)
- Y. Sonoda
- K. Okamoto
- N. A. Bhuiyan
- J. E. P. Fannon
- A. Takeda (ORCID: https://orcid.org/0009-0003-6003-072X)
- M. Malek
- M. C. Jang
- Volodymyr Takhistov (ORCID: https://orcid.org/0000-0003-2647-3431)
- T. Matsubara (ORCID: https://orcid.org/0000-0002-1233-6156)
- Keita Yamauchi (ORCID: https://orcid.org/0009-0000-0112-0619)
Institutions
- Boston University (US)
- Chonnam National University (KR)
- Tokyo Institute of Technology (JP)
- California State University System (US)
- Rutherford Appleton Laboratory (GB)
- University of Minnesota (US)
- Tokai University (JP)
- State University of New York (US)
- University of Hawaii System (US)
- Okayama University of Science (JP)
- University of Padua (IT)
- High Energy Accelerator Research Organization (JP)
- Seoul National University (KR)
- University of Liverpool (GB)
- Miyagi University of Education (JP)
- Tokyo University of Science (JP)
- Okayama University (JP)
- Kavli Institute for the Physics and Mathematics of the Universe (JP)
- Duke University (US)
- British Columbia Institute of Technology (CA)
- Yokohama National University (JP)
- King's College London (GB)
- University of Toronto (CA)
- Osaka Electro-Communication University (JP)
- Tohoku University (JP)
- Keio University (JP)
- University of California, Irvine (US)
- Kyoto University (JP)
- University of Minnesota System (US)
- Daresbury Laboratory (GB)
- California State University, Dominguez Hills (US)
- Gwangju Institute of Science and Technology (KR)
- University of Warwick (GB)
- University of Oxford (GB)
- Chonnam National University Hospital (KR)
- National Centre for Nuclear Research (PL)
- Institute for Basic Science (KR)
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari (IT)
- International Centre for Interdisciplinary Science and Education (VN)
- Laboratoire Leprince-Ringuet (FR)
- Shizuoka University of Welfare (JP)
- Istituto Nazionale di Fisica Nucleare, Sezione di Roma I (IT)
- Gifu University (JP)
- University of Toyama (JP)
- Institute for Cosmic Ray Research (JP)
- University of Warsaw (PL)
- Imperial College London (GB)
- Stony Brook University (US)
- Nagoya University (JP)
- Universidad Autónoma de Madrid (ES)
- Kobe University (JP)
- Polytechnic University of Bari (IT)
- The University of Tokyo (JP)
- University of Glasgow (GB)
- Sungkyunkwan University (KR)
- University of Silesia in Katowice (PL)
- The University of Winnipeg (CA)
- University of Sheffield (GB)
- Tsinghua University (CN)
Publication Details
- Journal
- Physical review. D/Physical review. D.
- Published
- 2024-10-25
- DOI
- https://doi.org/10.1103/physrevd.110.082008
- Primary Topic
- Neutrino Physics Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Energy
- Compute Canada
- Western Canada Research Grid
- European Commission
- National Research Foundation
- Ministry of Education, Culture, Sports, Science and Technology
- National Natural Science Foundation of China
- Ministry of Education
- Ministry of Science, ICT and Future Planning
- National Research Foundation of Korea
- Narodowe Centrum Nauki
- Ministerstwo Edukacji i Nauki
- Ministerio de Ciencia e Innovación
- Institute for Basic Science
- Horizon 2020 Framework Programme
- Natural Sciences and Engineering Research Council of Canada
- Science and Technology Facilities Council
- Japan Society for the Promotion of Science
- HORIZON EUROPE Marie Sklodowska-Curie Actions