分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: The topcolor-assisted technicolor (TC2) theory predicts tree-level flavor-changing neutral-current (FCNC) top quark Yukawa couplings with top-pions. Such FCNC interactions will induce like-sign top quark pair productions at CERN Large Hadron Collider (LHC). While these rare productions are far below the observable level in the Standard Model and other popular new physics models such as the Minimal Supersymmetric Model, we find that in a sound part of parameter space the TC2 model can enhance the production cross sections to several tens of fb and thus may be observable at the LHC due to rather low backgrounds. Searching for these productions at the LHC will serve as an excellent probe for the TC2 model.
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: The top-charm associated productions via e(+)e(-), e(-)gamma and gamma gamma collisions at linear colliders, which are extremely suppressed in the standard model ( SM), could be significantly enhanced in some extensions of the SM. In this article we calculate the full contribution of the top-color-assisted technicolor ( TC2) to these productions and then compare the results with the existing predictions of the SM, the general two-Higgs-doublet model and the minimal supersymmetric model. We find that the TC2 model predicts much larger production rates than other models and the largest-rate channel is gamma gamma -> t (c) over bar, which exceeds 10 fb for a large part of the parameter space. From the analysis of the observability of such productions at the future linear colliders, we find that the predictions of the TC2 model can reach the observable level for a large part of the parameter space while the predictions of other models are hardly accessible.