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Effect of heavy neutrinos in the weak bosons' pair production

Research Project

Project/Area Number 05640336
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 素粒子・核・宇宙線
Research InstitutionOCHANOMIZU UNIVERSITY

Principal Investigator

SUGAMOTO Akio  Ochanomizu Univ.Dept.physics Professor, 理学部, 教授 (70132686)

Co-Investigator(Kenkyū-buntansha) SHIRAISHI Kiyoshi  Akita J.College Economics Assoc.Prof., 商経科, 助教授 (80202117)
Project Period (FY) 1993 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,200,000 (Direct Cost: ¥1,200,000)
KeywordsHeavy neutrino / Electron, positron scattering / Weak bosons' pair production / Electro weak Baryogenesis / Phase transition dynamics / Vector-like quhrk makel / ep violation / Super symaetric model / 標準模型を越える模型 / ニュートリノ質量 / バリオン非対称
Research Abstract

1. Effects of the heavy neutrino in the 4th generation have been investigated in the e^+e^---> W^+W^- process, where 1) weak boson's 3 point formfactors, 2) differential cross sections, and 3) foreward-backward asymmetry was estimated. It has been shown that the neutrino type of Majorana or Dirac can be determined from the "threshold behavior of the scattering amplitudes", When the polarizd electron and positron beams are adopted as well as the polarization measurement of the final W' s can be performed. In the next collider energies the the heavy neutrinos' contibution to the cross sections is about 0.5%. 2. Baryogenesis at electoroweak scale has been studies using the heavy neutrinos. The lepton number generation rate has been estimated from the scattering of the neutrinos from the bubbles which appear in the development of the lstorder phase transition of our universe. Furthermore, simulation has been performed including the generation, fusion and growth effects of the bubbles, leading to the 2-3 times larger value for the produced to tallepton numbers. The observed value of the baryon number can be explained with the 100GeV and 50 GeV neutrinos at the phase transition temperature of 100K.3. CP violation effects in the weak boson's pair production processes have been studied in the model (1) with the heavy vector-like down-type quark, leading to the small value of 10^<-9>. In the supersymmetric standard model (2), however, a rather big value of 10^<-(4-5)> has been found due to the extra CP violationin the softly susy breaking term. 4. As the other baryogenesis model, the hyper-charge generation rate has been estimated in the presence of the up-type vector-like quark of 500 GeV,and the phase transition dynamics has been studied in this model. 5. Atmospheric neutrino problem has been examined in the 3 generation model of the neutrino oscillation.

Report

(4 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • 1993 Annual Research Report
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] A.Yamaguchi et al.: "Electroweak baryoglnesis and the phase transition dynamics" Mod.Phys.Cett.A. A9. 2599-2610 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Y.Katsuki et al.: "Majoraha Versus Dirac Neutrino in e^+e^-→W^+W^- through radiative Corectians" Phys.Cett.B. B354. 363-370 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] A.Sugamoto: "in the Proc.of the 23rd INS inthenatiral symposium on nuclear physics and particle physics with meson beams in the 1GeV/c region" Universal Academy Press,INC.-Tokyo Eds.S.Sugimoto and O.Hashimoto, 143-152 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] A.Yamaguchi et al.: "Elctroweak baryogenesis and the phasetransition dyramics" Mod.Phrs.Lett.A. A9. 2599-2610 (1994)

    • Related Report
      1995 Annual Research Report
  • [Publications] Y.Katsuki et al.: "Majoranao versus Dirac in e^+e^-→W^+W^- thwugh radiative corrections" Phys.Lett.B. B354. 363-370 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] A.Sugamoto: "in the “Prec of the 23nd INS in the national Sympasium or nuclear physics and partiole physics with morbeams in the 1Gevle regin" Univeusal Acadlmy Press,INC.-Tokyo.Eds.S.Sugimoto and O.Hashimoto, 143-152 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Azusa Yamaguchi: "Electroweak Baryogenesis and the Phase Transition Dynamics" Moderm Physics Letters A. 9. 2599-2610 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] Akio Sugamoto: "Baryon Asymmtry:Evidence of CP Vidation and Phase Trsnsition in the early waiverse?" 23rd INS Symposium Proceedings. (発表予定).

    • Related Report
      1994 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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