K介子稀有衰变及其对Multiscale WalkingTechnicolor模型的限制

在多标度人工色模型框架下计算了荷电PG玻色子     

Δr的实验测量与唯象分析

本文根据LEP和CDF等实验组的最新实验结果,导出了辐射修正因子Δr的实验值,并把该结果和根据标准模型理论计算得到的Δr理论值进行了比较.本文计算了全单圈和主要双圈的贡献,根据几率分布得到了对M_t比较严格的上限限制;当取Higgs粒子质量M_H=100GeV时M_t<175GeV(95%C.L.).本文还分析计算了其它实验误差和理论误差对M_t的影响.     

人工色荷电PG玻色子对B介子衰变中η′单举产率的增强

计算了人工色荷电PG玻色子π±1和π±8对稀有衰变过程B→η′X_s中η′单举产率的贡献.计算结果表明:QCD胶子反常和人工色新物理贡献能够提供较大的分枝比,以解释CLEO实验结果.     

Study of scalar meson a0（980） from B → a0（980）π decays

In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employing the perturbative QCD （pQCD） factorization approach at the leading order. We found that （a） the pQCD predictions for the branching ratios are around （0.4-2.8） × 10^-6, consistent with currently available experimental upper limits; （b） the CP asymmetries of B^0→ a0^0（980）π^0 and B^- → a0^- （980）π^0 decays can be large, about （70-80）% for α= 100°.     

B→K0^＊（1430）η（＇） decays in the pQCD approach

Based on the assumption of two-quark structure of the scalar meson K0^＊（1430）, we calculate the CP-averaged branching ratios for B→K0^＊（1430）η（＇） decays in the framework of the perturbative QCD （pQCD） approach here. We perform the evaluations in two scenarios for the scalar meson spectrum. We find that： （a） the pQCD predictions for Br（B→K0^＊（1430）η（＇）） which are about 10^-5 10^-6, basically agree with the data within large theoretical uncertainty; （b） the agreement between the pQCD predictions and the data in Scenario Ⅰ is better than that in Scenario Ⅱ, which can be tested by the forthcoming LHC experiments; （c） the annihilation contributions play an important role for these considered decays.     

B→（J/ψ,η_c）K decays in the perturbative QCD approach

In this paper,we calculated the B →（J/ψ,ηc） K decays in the perturbative QCD（pQCD） factorization approach with the inclusion of the partial next-to-leading order（NLO） contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors：Br（B0 → J/ψK0） = 5.2-＋32..58×10-4,Br（B＋ → J/ψK＋） = 5.6-＋32..79×10-4,Br（B0 →ηcK0） = 5.5-＋22..30 × 10-4,Br（B＋ →ηcK＋） = 5.9-＋22..51 × 10-4.     

Study of scalar meson a_0(980) from B→a_0(980)π decays

In this paper,we calculate the branching ratios and the direct CP-violating asymmetries for decays B0 →a00(980)π0,a0+(980)π-,a0-(980)π+ and B- →a00(980)π-,a0-(980)π0 by employing the perturbative QCD(pQCD) factorization approach at the leading order.We found that(a) the pQCD predictions for the branching ratios are around(0.4-2.8)×10-6,consistent with currently available experimental upper limits;(b) the CP asymmetries of B0 →a00(980)π0 and B- →a0-(980)π0 decays can be large,about(70-80)% for α=100-.     

Semileptonic decays B/Bs→(D?,D?s)lνl in the PQCD approach with the lattice QCD input

We study the semileptonic B/Bs→(D^?,D^?s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant transition form factors.We calculate the branching ratios B(B(s)→D^?(s)lνl)with l=(e,μ,τ),the ratios of the branching fractions R(D^?)and R(D^?s),and the physical observables Pτ(D^?(s)),FL(D?(s))and AFB(τ).The“PQCD+Lattice”predictions for B(B→D^?lνl)and R(D^?)agree with the available experimental measurements within errors.For the ratios R(Ds)and R(D^?s),the"PQCD+Lattice"predictions agree with the other predictions.For Pτ(D^?)and FL(D^?),our theoretical predictions agree with the measured values within errors.Our theoretical predictions of the semileptonic B/Bs decays considered could be tested in the near future by the LHCb and Belle II experiments.     

b→sγ在Multiscale Walking Technicolor模型中的研究

研究Multiscale Walking Technicolor模型(MWTCM)中赝标戈尔斯通玻色子(PGB)对b→sγ分支比的修正,发现修正太大以致很难解释最近CLEO的实验数据,如果进一步引入Topcolor,在Topcolor assistedMWTCM中,BR(b→sγ)在参数的一定空间内同CLEO的实验数据一致.     

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.