[Neutron] J-PARC project newsletter : special issue

[shibata_kaoru]

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     J-PARC Project Newsletter
                                       Special Issue, July 2013 Japan Proton Accelerator Research Complex under operation jointly by the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA).
http://j-parc.jp/index-e.html
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                                                    July 19th, 2013

  NEW RESULTS FROM T2K CONCLUSIVELY SHOW MUON NEUTRINOS
  TRANSFORM TO ELECTRON NEUTRINOS

                                                   T2K Collaboration
                  High Energy Accelerator Research Organization (KEK)
          Institute for Cosmic Ray Research, The University of Tokyo
                                                       J-PARC Center


  The T2K collaboration announced definitive observation of muon neutrino to electron neutrino transformation on July 19 at the 2013 European Physical Society conference on High Energy Physics in Stockholm, Sweden  ( http://eps-hep2013.eu/ ), which was also announced at the press conference as shown on the web, http://www.kek.jp/ja/NewsRoom/Release/20130719210000/ , http://legacy.kek.jp/intra-e/press/2013/071921/ .
In 2011 the collaboration announced the first indication of this process. Now with 3.5 times more data, an analysis reveals that there are more electron neutrinos (a total of 28 events) than would be expected (4.6 events) without this new process and this transformation is firmly established with 7.5 sigma level of significance.

Neutrino oscillation is a manifestation of a long range quantum mechanical interference.  Observation of this new type of neutrino oscillation leads the way to new studies of charge-parity(CP) violation. The T2K experiment expects to collect 10 times more data in the near future, including data with antineutrino beam for studies of CP violation in neutrinos.

This discovery was made possible with the unyielding and tireless effort by the J-PARC staff members and the management to deliver high quality beam to T2K after the devastating March 2011 earthquake in eastern Japan, which caused severe damage to the accelerator complex at J-PARC, and abruptly discontinued the data-taking run of the T2K experiment.

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Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto at kek.jp Kaoru SHIBATA: shibata.kaoru@ jaea.go.jp Takashi ITO: itou.takashi at jaea.go.jp Dick MISCHKE (English Editor): mischke at triumf.ca Junko BEANBLOSSOM (Secretary): beanblossom.junko at jaea.go.jp
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