Study Of The Processes Of E~+e~-(γγ)â†'b(?) In The LHT Model At Linear Collider

The standard model(SM) of elementary particle describing strong and electroweak interactions is a gauge theory. The SM has been extensively tested by the precise experimental data during the past 40 years, but the mechanism of electroweak symmetry breaking (EWSB) remains an open question and the scalar sector suffers from the problems of triviality and unnaturalness, etc. Thus the SM can only be an effective field theory below some high energy scale and it should be replaced by a profound and consistent new theory at higher energy. So people have done many active researchs and put forward some new physics models. For example, the supersymmetry (SUSY) theory, Technicolor model, little higgs model. Among these new physics models, littlest higgs model with T-parity (LHT) is now a very prevail.Searching for Flavor Changing Neutral Currents (FCNC) is one of important tasks at future high energy colliders. Due to the GIM mechanism in the SM, FCNC process is forbidden at tree level and sharply suppressed at loop level. In the new physics models beyond the SM, there exist some new flavor changing(FC) couplings and these FC couplings can significantly enhance the cross sections of the FC production processes. Based on the minimal supersymmetric model (MSSM), the general two-higgs-doublet model (2HDM), the topcolor-assisted technicolor (TC2) model and the littlest higgs model with T parity (LHT) etc, people have done many studies about the FC processes. Therefore, FC processes play an important role in searching for signal of new physics models. We just study the FC processes, e⁺e^- (γγ)→b(s|-), in the LHT model at international linear colliders (ILC). Such study can provide valuable theoretical instruction to test LHT model at experiments.The ILC with the center of the mass (c.m.) energy s = 300G eV -1.5TeV and the yearly luminosity 500 fb^-1 has been planned. In such a collider, in addition to e⁺e^- collision, one can also realize photon-photon collision. The ILC will be an ideal machine to probe new physics with high luminosity and clean background. In our work, we study the FC processes e⁺e^- (γγ)→b(s|-) at the ILC in the LHT model. Our study shows that with large masses of mirror quarks these two processes are accessible at the ILC. So the processes e⁺e^- (γγ)→b(s|-)at the ILC can provides a unique way to study the properties of the FC coupling in the LHT model and furthermore provides theoretical instruction to test LHT model and distinguish it from the other new physics models.