Ï„ Ï„ Lepton Decay Into Neutrinos And Quarks Lap QCD Correction Process Is Derived

The standard model （SM） in particle physics is one of the greatest achievements in physics of20th century, It is a gauge theory based on the gauge symmetry S U（2）_L×U（1）_Y, describing the fundermental interactions between elementary particles. Although its many predictions are in good agreement with high precision in the range of experimental errors, the higgs boson intimately related to the origin of the particle mass, has not been found. Therefore, the SM remains to be tested further.The r lepton is the most heavy charged lepton in SM particle spectrometer. The mass of the Ï„ lepton is much larger than the proton and hence alse is called heavy lepton. In view of the large mass, it’s expected that the Ï„ lepton might be closely connected with new physics beyond the SM. Therefor, it turns out that it plays very important roles in the deeper understanding of this lepon’s properties for searching and building the new physics model beyond the SM.the Ï„ lepton is unstable and it have many different decay mode. As is well known, the decay mode Ï„^-â†'v_Ï„+q₂+q₃is a weak process at the leading-order, but at the next-leading order the QCD corrections are expected to be very large because of the quarks involved in the decay mode. In the paper, we derived with many details the QCD correction to this important process. First the vertex functions of the interactions between W boson and two quarks and the quark self-energy are given, then calculated the renormalizaton constants for the quark fields and the mass parameter, and took into account the contribution of virtual gluons to cancel out the Ultra-violet divergences and include the real gluon radiations to remove the Infra-red divergeces. Finally, the final result is given.