分类: 物理学 >> 基本粒子与场物理学 提交时间: 2017-08-24
摘要: We explore the possibility that the observed baryon asymmetry of the universe is the result of an earlier phase transition in which an extended gauge sector breaks down into the SU(3)C × SU(2)L × U(1)Y of the Standard Model. Our prototypical example is the Topflavor model, in which there is a separate SU(2)1 for the third generation from the SU(2)2 felt by the first two generations. We show that the breakdown of SU(2)1 × SU(2)2 → SU(2)L results in lepton number being asymmetrically distributed through-out the three families, and provided the SM electroweak phase transition is not strongly first order, results in a non-zero baryon number, which for parameter choices that can be explored at the LHC, may explain the observed baryon asymmetry.
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2017-08-24
摘要: If a new massive vector boson with nonzero axial couplings to fermions will be observed at LHC, then an upper limit on the scale of new physics could be derived from unitarity of S-matrix. The new physics will involve either new massive fermions, or scalars, or even a strongly coupled sector. We derive a model independent bound on the scale of new physics. If MG/g A < 3 TeV and the fermion is a top quark, the upper limit is 78 TeV.