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Effect of heavy neutrinos in the weak bosons' pair production

重中微子对弱玻色子对产生的影响

基本信息

批准号：
05640336
负责人：
SUGAMOTO Akio
金额：
$ 1.41万
依托单位：
OCHANOMIZU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05640336/
关键词：
Heavy 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

项目摘要

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.

1. 在e^+e^—> W^+W^-过程中研究了第四代重中微子的效应，其中1)弱玻色子的三点形因子，2)微分截面和3)前后不对称估计。结果表明，当采用极化电子束和正电子束时，可以根据“散射振幅的阈值行为”确定马约拉纳或狄拉克中微子的类型，并可以进行最终W的极化测量。在下一个对撞机能量中，重中微子对横截面的贡献约为0.5%。2. 用重中微子研究了电弱尺度下的重子发生。轻子数的产生率是由在我们宇宙的较长相变发展过程中出现的气泡的中微子散射估计出来的。此外，还对气泡的产生、融合和生长效应进行了模拟，结果表明，气泡产生的总轻子数增大了2-3倍。重子数的观测值可以用100GeV和50gev的中微子在100K.3的相变温度下解释。用重的类矢量下型夸克模型(1)研究了弱玻色子对产生过程中的CP违逆效应，得到了10^<-9>的小值。然而，在超对称标准模型(2)中，由于软软破缺项中额外的CP违背，发现了一个相当大的值10^<-(4-5)>。4. 作为另一种重子生成模型，我们估计了500 GeV的上型类矢量夸克存在时的超电荷生成速率，并在该模型中研究了相变动力学。5. 在中微子振荡的3代模型中研究了大气中微子问题。