Huang Jin-Shu

Top quark pair production at e(+)e(-) colliders in the topcolor-assisted technicolor model

In the framework of topcolor-assisted technicolor model we calculate the contributions from the pseudo Goldstone bosons and new gauge bosons to c(+)c(-) --> t (t) over bar. We End that for reason able ranges of the parameters, the pseudo Goldstone bosons afford dominate contribution, the correction arising from new gauge bosons is negligibly small, the maximum of the relative corrections is similar to 10% with the center-of-mass energy roots- = 500 GeV; whereas in the case of roots- = 1500 GeV, the relative corrections could be up to 16%. Thus large new physics might be observable at the experiments of next-generation linear colliders.

Associated production of a neutral top-Higgs with a heavy-quark pair in the γγ collisions at ILC

We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in γγ collisions at the International Linear Collider (ILC). We find that the cross section for tht in γγ collisions is at the level of a few fb with the am. energy √s = 1000 GeV, which is consistent with the results of the cross section of tH in the standard model and the cross section of tth in the minimal supersymmetric standard model. It should be clear that hundreds of to thousands of ht per year can be produced at the ILC. This process of γγ → tht is really interesting in testing the standard model and searching the signs of technicolor.We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in γγ collisions at the International Linear Collider (ILC). We find that the cross section for tt̄ht in γγ collisions is at the level of a few fb with the c.m. energy √ s = 1000 GeV, which is consistent with the results of the cross section of tt̄H in the standard model and the cross section of tt̄h in the minimal supersymmetric standard model and the littlest Higgs models. It should be clear that hundreds of to thousands of ht per year can be produced at the ILC. This process of γγ → tt̄ht is really interesting in testing the standard model and searching the signs of technicolor.

Searches for the technicolor signatures via gg → W±πt∓ at the Large Hadron Collider

In this paper, we calculate the production of a charged top pion in association with a W boson via gg fusion at CERNs Large Hadron Collider in the context of the topcolor assisted technicolor model. We find that the total cross section of pp → gg → W±πt is several dozen femtobarns with reasonable values of the parameters, and the total cross section of pp → W±πt can reach a few hundred femtobarns when we consider the sum of the contributions of these two parton subprocesses, gg → W±πt and b → W±πt.

W±πt∓ Associated Production at Large Hadron Collider*

In this paper we calculate the production of a charged top pion in association with a boson at the CERN Large Hadron Collider (LHC) in the context of the topcolor assisted technicolor model. We find that the cross section of is roughly corresponding to the result of the process in the minimal supersymmetric standard model, and for reasonable ranges of the parameters, the cross section can reach a few hundred fb. The signal should be clearly visible at LHC unless is very heavy.

Constraints on Technicolor Models from Inclusive Decay of B Meson

Corrections to the branching ratio BR(B → Xsγ) from technipions and top pions appeared in technicolor models are investigated. We found that: (a) the multiscale walking technicolor model is ruled out since it is conflict with the CLEO data; (b) the topcolor-assisted technicolor model is consistent with the CLEO data of BR(B → Xsγ) for a certain range of parameters.

Properties of the coupling constants of J/ψ → VP decays

Based on the branching fractions of J/psi -> VP from different experiments, we investigate the properties of the coupling constants of J/psi -> VP decays using a model-dependent approach. We find that the octet coupling constant, g(8), of strong interaction is about twice larger than that of the singlet coupling constant g(1); the electromagnetic breaking parameters g(M)(i) are larger than the mass breaking parameters g(M)(i), moreover, the three parameters of the electromagnetic effect are about equal, but the three parameters of the mass effect are obviously different and their uncertainties are also large; and the phase angle between strong and electromagnetic interactions is in the range of 70 degrees-80 degrees. It deepens our understanding of the coupling constant of J/psi -> VP decays.

Bs ? varphi?0 Decay in the Extra Down-Type Quark Model

Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs → π0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs ? ?0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.

Bs → φπ0 Decay in the Extra Down-Type Quark Model

Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs → π0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs ? ?0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.

Bs → varphiπ0 Decay in the Extra Down-Type Quark Model

Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs → π0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.Using the QCD factorization approach, we investigate the electro-weak penguin dominated process Bs ? ?0 in the extra down-type quark (EDQS) model. We calculate the effects of new physics (NP) on the branching fraction and direct CP asymmetry of the decay mode. It is found that the branching fraction can be increased by 15% points or dropped by 13% points than the standard model (SM) value, and its direct CP asymmetry can be increased by 35% points or dropped by 37% points than the SM one. The effects of NP on the direct CP asymmetry are more obvious than on the branching fraction. If this decay mode could be measured in the upcoming LHCb experiment, these results we obtain will be useful for further studies of the EDQS model.

Study onBd→ ϕKSDecay in EDQS Model

We study Bd → KS decay in extra down-type quarks (EDQS) model with a non-universal Z boson associated with flavor changing neutral currents (FCNCs) at the tree level. With the up-to-date experimental data of Br(Bd → KS), SKS, and AKS, we derive the bounds on the Z-b-s coupling parameter |Ubs| and the new weak phase , using the constrained parameter spaces, we finally give predictions for Bs → decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.