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.     

高能e+e-对撞机上top介子辅助的b夸克对产生

在顶色辅助的人工色模型下计算了高能e^ e^-对撞机上top介子辅助的b夸克对产生过程e^ e^-→bb^-π^0t的产生截面．发现在一定的参数范围内，这个过程的产生截面大于lOfb，比标准模型下标量Higgs粒子辅助的b夸克对产生过程大许多，与最小超对称模型下标量和赝标量Higgs粒子h^0，H^0，A^0的相应产生截面大致相当．人工色理论的信息可能在下一代正负电子对撞实验中探测到．     

Study of the e+e- to hadrons via ISR at BABAR

Experimental data from the PEP-Ⅱ B-factory at 10.6 GeV center-of-mass (c.m.) energy, obtained via initial-state radiation (ISR) with the BABAR detector, are presented. The cross sections for many hadronic processes have been measured from the production threshold to 4-5 GeV of the e+e- c.m. Energy. The obtained data allow to study a number of intermediate states and determine the parameters of known resonances and their branching fractions. The exclusive cross section for some number of hadronic sub-processes are presented.     

高能电子-正电子碰撞中产生喷注的标度

对高能电子-正电子对撞产生实验上可以直接观察的可视喷注的标度进行了仔细研究.根据在s=17—30Gev的电子-正电子对撞实验中最先观察到三喷注这一历史事实,论证了可视喷注的相对横动量kt.在5—10GeV/c的范围.并通过一个具体例子说明,只有k_t在这一范围时才能正确地判定事件中的喷注数.仔细比较了由不同k_t得到的喷注内部的动力学起伏,发现只有k_t在5—10GeV/c范围时,喷注内部系统才有最好的反常标度性.从而得到,可视喷注的标度是k_t～5—10GeV/c.讨论了这一标度和微扰QCD的标度1—2GeV之间的关系.     

TC2模型下的顶夸克稀有衰变t→cV

在顶色辅助的人工色(TC2)理论框架下,研究了顶夸克稀有衰变t→cV过程.结果表明TC2模型预言的标量粒子top-pions和top-Higgs对顶夸克稀有衰变分支比的贡献可以使其比标准模型预言值大6—9个数量级.在大多数参数范围内,分支比的数量级为:Br(t→cg)～10^－5,Br(t→cZ)～10^－5,Br(t→cγ)～10^－7.在合理的参数范围内,顶夸克稀有衰变t→cV过程能够被未来的对撞机实验探测到.因此,顶夸克稀有衰变过程为我们提供了一种检验TC2理论的方法.     

Production of charmonium(like) states in e+e- interactions

We present a search for new charmonium like states in e+e- annihilation using the initial-state radiation and the process e+e-→J/ψ D(*)D(*). The analyses are based on a huge data sample recorded near the T(4S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider.     

Effects of a Family Non-universal Z' Boson in \bar{B}_d→μ+μ- and B- →π-μ+μ-,ρ-μ+μ- Decays

Motivated by the recently updated experimental measurement on \bar{B}_d→μ⁺μ^- and B^-→π^-μ⁺μ^- decays by CDF and Belle collaborations, we revisit these
decays, as well as B^-→ρ^-μ⁺μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z' boson. Under the constraint from {\cal B}(B^-→π^-μ⁺μ^-), we find the ranges of the Z' couplings S^LR_μμ< -5.2×10^-2 or D^LR_μμ < -8.1× 10^-2 are excluded. Within the allowed Z' parameters spaces, comparing with the SM predictions, we find that {\cal B}(\bar{B}_d→ μ⁺μ^-, {\cal B}(B^-→ π^-μ⁺μ^-), and {\cal B}(B^-→ρ^-μ⁺μ^-) could be enhanced by a factor about
226%, 245%, and 254%, respectively, byZ' contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^- →ρ^-μ⁺μ^- decay at low dimuon mass always exists.     

Top-Higgs和top-charm在高能正负电子对撞机上的联合产生

在顶色辅助的人工色(TC2)模型框架下, 研究了top-Higgs和t-c夸克的联合产生过程e⁺e^-→tch_t⁰.结果显示此过程的产生截面在合理的参数空间内可达到10fb, 在高能直线对撞机(LC)上每年可产生几百个事例. 通过此过程可用来探测top-Higgs.     

ILC上e~+e~-对撞产生t~+t~-夸克对

本文结合国际直线对撞机(ILC)的实验讨论了e+e-湮灭产生t+t-对过程.在具体计算过程中,本文采用一种新的计算方式,即"混合链图传播子"修正下的反应截面,首先对QED中Dyson链图传播子理论在电弱统一标准模型(WS)中做了推广,获得WS中的光子、中间玻色子混合链图传播子,进而计算了γ,Z0混合链图修正下e+e-→t+t-反应总截面σchain,并与单圈修正下的总截面σloop和最低阶总截面σ0做了对比分析,发现在国际直线对撞机对撞能区,σchain对σloop和σ0的修正很大.此外,作者还结合国际直线对撞机的对撞亮度,讨论了每年可在ILC上产生t+t-对的事例数.     

Rare Decay B → Xsvv in the Two-Higgs-Doublet Model of Type-Ⅲ

In this paper, we calculated the new physics contribution to theoretically very clean rare decay B → Xsvvin the general two-Higgs-doublet model (model Ⅲ). Within the considered parameter space, we found that (a) thenew physics contribution can provide one to two orders of enhancement to the branching ratio B(B → Xsvv) and cansaturate the experimental bound on B(B → Xs vv) in some regions of the parameter space; (b) besides the CLEO data ofB → Xsγ, the ALEPH upper limit on B(B → Xsvv) also leads to further constraint on the size of the Yukawa couplingλtt: λtt ＜ 6.4 for λbb = 2.7 and mH+ = 200 GeV.     

Energy dependence of non-linear dynamical features in e+e- collisions

A study of the dynamical fluctuation properties at various c.m. Energies in e+e- collisions is performed using the Monte Carlo method. The results suggest that, after the normalized factorial moments of 3-dimensional phase space are analyzed using an isotropical phase space partition, the NFM describing non-linear dynamical properties show a power-law scaling, I.e., the dynamical fluctuations in higher dimensional phase space are isotropic. For c.m. Energies √s≤80 GeV,the scaling exponents φq increase rapidly with the c.m. Energy and for c.m. Energies √s＞80 GeV,the φq gradually saturate.     

正负电子对撞多粒子末态的动力学起伏

运用Jetset产生器分别在实验室系和冲度轴坐标系中对e⁺e^—对撞多粒子末态中阶乘矩的标度性质进行了研究.在这两种情况下,用各向同性的相空间分割得到的三维InF₂～InM都近似于直线,表明e⁺e^－对撞末态相空间中的动力学起伏近似各向同性.在实验室系中由p_x,p_y,p_z的F²～M拟合Ochs公式得到的三个γ值近似相等;在冲度轴系中,在φ方向上适当选取起始拟合点,三个γ值也比较相近,进一步肯定了这一论断.这一结果表明,软、硬过程动力学起伏的本质特征──各向异性或(近似)各向同性,可以通过碰撞过程中阶乘矩标度性质的研究而揭示出来.因此,深入研究各种碰撞过程中阶乘矩的标度性质,对于了解碰撞动力学的本质有重要意义.     

Measurement of the absolute branching fraction of D+→K0e+ve via K0→π0π0

By analyzing 2.93 fb^-1 data collected at the center-of-mass energy √s=3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D⁺→K⁰e⁺v_e to be B(D⁺→K⁰e⁺v_e)=(8.59±0.14±0.21)% using K⁰→K_S⁰→π⁰π⁰, where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..     

Detection of Charged Higgs Bosons in e+e-(γγ)→tbφ- Production at the ILC

In the context of the left-right twin Higgs (LRTH) model, we have studied the charged Higgs bosons production processes e⁺e^-(γγ)→tbφ^- at the International Linear Collider (ILC). It is found that the cross sections of these two processes could reach a few fb with reasonable parameter values. With the yearly integrated luminosity of L=500 fb^-1 expected at the ILC, one could collect hundreds up to thousands of charged Higgs events via these two processes. Therefore, our researches in this paper can help us search for charged Higgs bosons, and furthermore, to test the LRTH model.     

The Spin‐Charge‐Family Theory Offers Understanding of the Triangle Anomalies Cancellation in the Standard Model

The standard model has for massless quarks and leptons “miraculously” no triangle anomalies due to the fact that the sum of all possible traces — where and are the generators of one, of two or of three of the groups and U (1) — over the representations of one family of the left handed fermions and anti‐fermions (and separately of the right handed fermions and anti‐fermions), contributing to the triangle currents, is equal to zero. 1 - 4 It is demonstrated in this paper that this cancellation of the standard model triangle anomaly follows straightforwardly if the and are the subgroups of the orthogonal group , as it is in the spin‐charge‐family theory. 5 - 22 We comment on the anomaly cancellation, which works if handedness and charges are related “by hand”.