AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Lepton definition physics4/29/2023 ![]() Gauge-invariant lepton part of the Lagrangian density of WS model can be written asīy defining the mass eigenstates of gauge fields With the chiral fermions given in Equation (1) and Equation (2), the most general ![]() In the standard WS model, the usual default setting is that the flavor eigenstates of charged leptons are the same as their mass eigenstates (An eigenstate of finite mass is a superposition of left and right-handed states with equal weight ), i.e., While the right-handed sector consists of an isosinglet, the right-handed charged lepton:ĭenote the flavor indexes of the charged leptons, and the subscripts L and R refer to the left- and right-handed components, respectively. The left-handed fermions form an isodoublet, consisting of the neutrino and the charged lepton: Observationally, we must incorporate a neutral, left-handed neutrino (For simplicity, the neutrino is assumed to be massless, and hence right-handed neutrino is absent.) along with a charged lepton, which can be considered to be the sum of left-handed and right-handed Weyl spinors. Let’s start with discussing the lepton sector. Therefore, in the present paper, for simplicity, we will limit ourselves to three generations of leptons. Since quarks are supposed to be confined by virtue of their strong interactions, the meaning of the quark mass is not obvious. In the WS model, there are three generations of quarks and leptons with identical quantum numbers but different masses. Quarks and leptons constitute the basic building blocks of matter in the standard model. ![]() Since the fermion masses are related to the Yukawa couplings, we can only understand these differences and the mass-generation phenomenon by studying the Yukawa couplings in detail. We do not know why there exists such a large difference among the masses of these fermions, and we have no deep understanding of the origin of these masses. But for the fermionic sector, the fermion mass spectrum ranges from 170 GeV of the top-quark to 0.511 × 10 −3 GeV of the electron. , is used to understand numerous neutral-current data. ![]() The success of the WS model only involves the gauge sector of the theory, in which only one free parameter, the Weinberg angle For example, the model is based on too many assumptions and leaves many fundamental questions unanswered. Although the WS model has achieved impressive success in correlating all observed low-energy data in terms of a very few parameters, it cannot be called perfect. Up to now, with the discovery of the 125 GeV Higgs boson in 2012 at the CERN LHC, the Weinberg-Salam (WS) model of the electroweak interaction of particle physics stands triumphant, and almost all relevant experimental results in particle physics are consistent with this model. ![]()
0 Comments
Read More
Leave a Reply. |