One Loop Effects to the Process e+e－→bs in Topcolor-Assisted Multiscale Technicolor Model

We calculated the Pseudo-Goldstone bosons (technipions, top-pious) corrections to the cross-section a of the process e⁺e^－→bs in topcolor-assisted multiscale technicolor model at LEP Ⅱ energy region. Our results show that, with reasonable value of the parameters, the cross-section is one order larger than that predicted by the standard model. We discussed the possibility of detecting this rare event at the B-factoly.     

Topcolor-Assisted Technicolor and the Decay Bc → Ds*γ

Applying the perturbative QCD method, we study the process B_c → D_s^*γ in the topcolor-assisted technicolor model (TATCM), and compare the results with those estimated in the standard model (SM). There are two mechanisms which contribute to the B_c → D_s^*γ process. One proceeds through the short distance b → sγ transition, the other through weak annihilation accompanied by a photon emission. The contribution of weak annihilation is found to be much more important than that of tlie electromagnetic penguin in the TATCM, and the branching ratio, BR (B_c → D_s^*γ), is much smaller than that in the SM.     

TC2模型中的TC介子对e+e-→(t-)c过程的贡献

计算了Topcolor辅助的人工色模型中的赝标哥尔斯通玻色子对超高能正负电子对撞机上的e+e-→(t-)((c-)t)过程的修正. 发现在质心能量为(s)=200GeV时新物理对该过程的修正结果比标准模型的结果高出约1个量级. 如果选取质心能量为(s)=500GeV得到的结果为σ(e+e-→(t-)c)～10-37cm2.     

具有标量粒子的人工色模型下稀有辐射衰变b→Xsγ的研究

在具有标量粒子的人工色模型下计算了遍举衰变b→Xsγ的O(α_s)修正.发现当使用ALEPH实验数据时,此模型预言的衰变宽度可以减少到标准模型值的50%.CLEO实验下限与标准模型值相比较减少了33%,它比B→B混合对此模型参数空间的限制更严.此模型预言的b→Xsγ分支比在部分参数空间上与标准模型有大的偏差,有望在即将投入运行的升级CLEO探测器和B介子工厂上观察到.     

OGTC模型中PGBs对γγ→bb过程的Yukawa修正

计算了一代人工色(One Generation Technicolor,简称OGTC)模型中的赝标哥尔斯通玻色子(Pseudo-Goldstone Bosons,简称PGBs)对γγ→bb过程的Yukawa修正.发现在一定的参数范围内,PGBs对γγ→bb散射截面的修正超过10%;而PGBs对过程e⁺e^－→γγ→bb的相对修正,在laser back-scattering photons模式下最大可达－51%,在beamstrahlung photons模式下最大只有－17.9%;这些修正比标准模型和超对称模型下相应粒子的贡献大许多,将为在下一代高能光子碰撞实验上寻找人工色理论的信息提供参考.     

Rare Radiative Decay b→Xsγ in the Technicolor with Scalars Model

The O(α_s) correction to the inclusive decay of b→X sγ is calculated in the technicolor model with scalars. We find that the deviation of the decay width from the standard model prediction can be reduced by as much as 50% when ALEPH experimental value is used. In particular,the CLEO measurement which corresponds to the 33% reduction gives more stringent constraint on the parameter space in the technicolor with scalars model than B-B mixing. The model predictions can be observable in the forthcoming few years with upgraded CLEO detector and B-factories.     

Study on B → φK * and B d → φK S decays in a flavor changing Z′ model

We study the polarization anomaly of the B _d → φK ^*0 decay and the time-dependent CP asymmetry S _φKS of the B _d → φK _S decay in a Z′ model associated with flavor changing neutral currents at the tree level. We obtain the results of 0.0113 < ξ < 0.0127 and 0.0226 < ξ < 0.0255 for the two decay processes when setting ξ _LL = ξ _RL = ξ _LR = ξ _RR = ξ, ξ _LL = ξ _RL = ξ, and ξ _LR = ξ _RR = 0, respectively. These results are consistent with the constraints and assumptions on the model parameters in some references. Supported by the National Natural Science Foundation of China (Grant No. 10575029), the Natural Science Foundation of Henan Province of China (Grant No. 0611050300), the Natural Science Foundation of Henan Provincial Educational Committee (Grant No. 2007140013), and the High-qualified Talents Scientific Research Startup Foundation of Nanyang Normal University (Grant No. nytc2006k92)     

Rare Decays B → XS,dνν and XS,d → l+l- in the,Topcolor-Assisted Technicolor Model

We calculate the contributions to the rare decays B → X_S,dνν and X_S,d → l⁺l^- from one-loop Z^o -penguin diagrams in the framework of topcolor-assisted technicolor model. Within the parameter space, we find that: (a) the new contribution from technipions is less than 2% of the standard model prediction; (b) the top-pions can provide a factor of 10 to 30 enhancement to the ratios in question; (c) the topcolor-assisted technicolor model is consistent with the current experimental'data.     

The Signatures of the Neutral Top-Pion at the NLC and the Tevatron in Topcolor-Assisted MWTC Model

The neutral top-pion π_t⁰ can couple to the gluons and the photons through the top quark triangle-loop. we calculate the corrections of the neutral top-pion π_t⁰ to the tt production cross section in topcolor-assisted multiscale walking technicolor model. We find that, for a heavy neutral top-pion, the corrections are quite significant. For m_t = 175 GeV, 5 GeV ≤ m_t¹ ≤ 20 GeV and M_πt = 350 GeV, the relative correction Δσ/σ₀ is larger than 10% which might be observed at a high-luminosity Tevatron. We further estimate the production cross section of π_t⁰ at the NLC experiment. We find that the production rate is significantly large. The neutral top-pion π_t⁰ may be detected in future e⁺e^- linear collider experiments.     

顶色辅助的多标度人工色理论对稀有过程e~ e~-→s的单圈效应

讨论了顶色辅助的多标度人工色理论预言的赝标哥尔斯通玻色子（ｔｅｃｈ－ ｎｉｐｉｏｎｓ,ｔｏｐ－ｐｉｏｕｓ）对稀有过程ｅ＋ｅ－→ｂｓ的单圈效应,计算了该过程在ＬＥＰⅡ上 的产生截面,得到较标准模型预言值要大一个数量级的数值结果．并进一步讨 论了在Ｂ介子工厂上探测此稀有过程的可能性．