Study Of Particle Physics With Intense Fields

Recent advances in laser technology lead to the result that upcoming high-intensity laser systems will be able to probe the quantum-induced nonlinear electrodynamics. Such laser systems provide an effective tool for investigating fundamental physics. So far unobserved QED phenomena such as the discovery of vacuum polarization effects can become accessible. In this thesis, we investigate some important fields of particle physics with intense fields:1. Study of radiation damping. Due to the existence of controversial problems such as runaway and preacceleration solutions, the dynamics for charged particle with radiation damping has confused us for many years. Here we investigate the effects of Lorentz-Abraham-Dirac(LAD) equation at second order, inspiring from the Landau-Lifshitz(LL) equation which is the first order perturbation of LAD equation. A formu-lation for the dynamics of charge particle is presented. Detailed studies on this equation show that the perturbation in the LL equation is very successful. Because such param-eters region is existent that even the first order of the perturbation is larger than the Lorentz force, the second order of the perturbation is very small. When increasing the field strengths, the energy of the incident photon and the initial energy of electron, the effect of the second order increases. When the field strengths, the energy of the in-cident photon and the initial energy of electron are large enough, the second order is comparable with the first order or the Lorentz force.2. Study of Axion-like particles. Axions are pseudoscalars that result from the Peccei-Quinn solution to the strong CP problem. These hypothetical particles play an important role in strong field physics, particle physics, astrophysics, and cosmology. Here we calculate the two-loop contribution of lepton's electric dipole moments in-duced from a scalar without definite parity. Unfortunately, the coefficient of leading term was exactly zero.3. Study the decay of unstable particles in intense fields. The modifications of the properties of elementary particles due to the presence of a strong field are enjoying a lot of attention. Here we do a calculation of the muon decay in a laser field, in the Furry picture based on the Volkov solution. We verify the old result of Ritus. Detailed studies show that the muon lifetime would not be evidently changed in the currently available laser pulse.