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Search for New Physics Using B Meson Decay to Tau Lepton and Neutrino

Research Project

Project/Area Number 24740157
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionNagoya University

Principal Investigator

HORII Yasuyuki  名古屋大学, 理学(系)研究科(研究院), 助教 (80616839)

Project Period (FY) 2012-04-01 – 2015-03-31
Project Status Completed (Fiscal Year 2014)
Budget Amount *help
¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
KeywordsB中間子 / Belle実験 / タウ / ニュートリノ / 荷電ヒッグス
Outline of Final Research Achievements

We measure the branching ratio of B->taunu using the full data sample collected at the Belle experiment. Events with B meson pairs are tagged by reconstructing one of the B mesons decaying into hadronic final states, and B->taunu candidates are detected in the recoil. We find evidence for B->taunu with a significance of 3.0 standard deviations. By combining with the result based on a tag of B meson pairs using semileptonic decays, the branching ratio is evaluated to be (0.96+-0.26)x10-4. A stringent constraint is obtained for the ratio of the vacuum expectation values and the charged Higgs mass in Type II of two Higgs doublet models.
To improve the precision on B->taunu, we have developed a new particle identification system. Optical performance of the quartz radiator, which is a main component of the system, has been measured to be sufficiently high. The method of gluing multiple quartz bars for obtaining a full size of about 2.7 meters has been established.

Report

(4 results)
  • 2014 Annual Research Report   Final Research Report ( PDF )
  • 2013 Research-status Report
  • 2012 Research-status Report
  • Research Products

    (10 results)

All 2013 2012 Other

All Journal Article (1 results) (of which Peer Reviewed: 1 results) Presentation (6 results) (of which Invited: 4 results) Remarks (3 results)

  • [Journal Article] Evidence for B- → τ- ντ-bar with a Hadronic Tagging Method Using the Full Data Sample of Belle2013

    • Author(s)
      K.Hara et al
    • Journal Title

      Phys. Rev. Lett.

      Volume: 110 Issue: 13 Pages: 131801-131801

    • DOI

      10.1103/physrevlett.110.131801

    • Related Report
      2012 Research-status Report
    • Peer Reviewed
  • [Presentation] B->taunu and B->D(*)taunu at Belle and BaBar2013

    • Author(s)
      Y. Horii
    • Organizer
      14th International Conference on B-Physics at Hadron Machines
    • Place of Presentation
      Bologna, Italy
    • Related Report
      2013 Research-status Report
    • Invited
  • [Presentation] TOP Counter for Particle Identification at the Belle II Experiment2013

    • Author(s)
      Y. Horii
    • Organizer
      The 2013 European Physical Society Conference on High Energy Physics
    • Place of Presentation
      Stockholm, Sweden
    • Related Report
      2013 Research-status Report
  • [Presentation] Leptonic and semileptonic B decays with tau at the B factories2012

    • Author(s)
      Y. Horii
    • Organizer
      XIth International Conference on Heavy Quarks and Leptons 2012
    • Place of Presentation
      Prague, Czech Republic
    • Related Report
      2012 Research-status Report
    • Invited
  • [Presentation] Belle実験におけるハドロンタグを用いたB->taunu崩壊の解析2012

    • Author(s)
      堀井泰之, 他 Belle Collaboration
    • Organizer
      日本物理学会2012年秋季大会
    • Place of Presentation
      京都産業大学
    • Related Report
      2012 Research-status Report
  • [Presentation] Measurement of B->taunu2012

    • Author(s)
      Y. Horii
    • Organizer
      The 12th International Workshop on Tau Lepton Physics
    • Place of Presentation
      名古屋大学
    • Related Report
      2012 Research-status Report
    • Invited
  • [Presentation] B → τν/μν/eν - Belle results and outlook for Belle II2012

    • Author(s)
      Y. Horii
    • Organizer
      7th International Workshop on the CKM Unitarity Triangle
    • Place of Presentation
      University of Cincinnati, USA
    • Related Report
      2012 Research-status Report
    • Invited
  • [Remarks] Home Page of Y. Horii

    • URL

      http://www.hepl.phys.nagoya-u.ac.jp/~yhorii.nagoya/

    • Related Report
      2014 Annual Research Report
  • [Remarks] Home Page of Y. Horii

    • URL

      http://www.hepl.phys.nagoya-u.ac.jp/~yhorii.nagoya/

    • Related Report
      2013 Research-status Report
  • [Remarks] Home Page of Y. Horii

    • URL

      http://www.hepl.phys.nagoya-u.ac.jp/~yhorii.nagoya/

    • Related Report
      2012 Research-status Report

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Published: 2013-05-31   Modified: 2019-07-29  

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