Neutral weak leptonic interaction

First, the weak interaction quanta became massive at the temperature scale of 100 GeV. Since then, weak reactions have only occurred in contact interactions of the particles. At about the same time the t-quark and the Higgs quanta also decoupled from the soup. The same decoupling happened for the other heavy quark species (b-quark, c-quark) and for the heaviest of the leptons (r-particle) in the range 1-5 GeV (a few times lO K) of the average energy density. The x-neutrinos remain in thermal equilibrium via weak neutral interactions. 

We here enlarge the standard model to include the weak and electromagnetic interactions of hadrons. We encounter serious techniceil problems if we try to restrict ourselves to the original three quarks, u,d,s. In particular we find unwanted neutral strangeness-changing currents in the theory. These difficulties are eliminated by the introduction of a new charm quark c. There is then a very attractive universality between the two lepton doublets (e-) ( - ) quark doublets formed from... 

Neutrinos of all types, Vg, v, and Vr, can scatter elastically from an electron. This process is a result of the weak-interaction coupling between the neutrino and the charged lepton, a coupling that may have a charged and a neutral current component. The cross section for scattering from electrons depends on the neutrino type, Vg, and whether it is a neutrino or an antineutrino. Only the electron neutrino is coupled to the electron by both the charged and the neutral currents, whereas other neutrino types are coupled by neutral currents. These reactions may be represented schematically as follows ... 

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