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^－→bbπ0t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10fb,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h⁰,H⁰,A⁰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.     

中能K+核弹性散射光学势参数

采用包含库仑场影响的一级修正的eikonal相移研究了入射动量为715MeV/C的K⁺介子与⁶Li、¹²C核散射及入射动量为800MeV/c的K⁺介子与(12)C、⁴⁰Ca核散射的微分截面,通过理论微分截面与相应实验数据的拟合,得到了最佳光学势参数,为K⁺核散射的微观研究提供一定依据.用得到的光学势计算了相应散射过程的总截面,并与实验值作了比较.     

KK强相互作用束缚态及K+K－原子态的研究

讨论了KK的强相互作用单介子交换势, 发现当考虑动量平方项时, 仅由单介子(ρ,ω,φ)交换势, 不足以构成束缚态. K⁺K^－在库仑势的作用下可以形成束缚态, 我们进一步计算了单介子交换势对K⁺K^－库仑势束缚态能级的影响以及K⁺K^－束缚态衰变到ππ和ηπ的宽度.     

顶色辅助的多标度人工色理论对稀有过程e+e－→bs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.     

Pentaquark Θ+对核物质状态方程的影响

假定Θ⁺通过交换有效的同位旋标量介子σ和ω与核子和它本身发生相互作用, 在密度相关的相对论平均场理论基础上研究了{p,n,Θ⁺}系统状态方程和可能形成的亚稳定态. 讨论了在不同的重子密度下质子-中子同位旋比值以及Pentaquark Θ⁺成分对系统单个重子能的影响. 计算结果表明, 在单个重子能取极小时, Θ⁺有可能在核物质中束缚存在.     

现实的一代ETC模型对Zbb、Zτ+τ－顶角的辐射修正

在一个现实的一代扩展人工色(ETC)模型中,计算了旁路(Sideways)及对角(diagonal)ETC规范玻色子交换对Zbb、Zτ⁺τ^－顶角的单圈辐射修正.结果表明Z→bb过程的衰变宽度Γ_b、分支比R_b以及τ的极化不对称参数A_τ都较标准模型的要大,与最近的实验数据相符.     

高能核碰撞中的K+/π+比与次级碰撞效应

用程函近似分析在高能核碰撞中次级作用对K⁺/π⁺比的影响.计算表明,在K⁺/π⁺比中次级碰撞效应是重要的.     

利用BESⅢ的双层TOF寻找D0-D0混合的研究

在ψ(3770)处, D⁰→K^－π⁺是研究D⁰-D⁰混合的非常理想的衰变道. 实验上, 良好K/π识别技术将对寻找D⁰-D⁰混合过程起着决定性的作用. 在BESⅢ实验的物理预研究中, 发现利用飞行时间的信息, 能够精确测定末态中含有多条带电径迹事例的起始时间, 从而可以改善飞行时间计数器的时间分辨率. 进一步的研究表明, 应用该方法后, BESⅢ双层TOF的时间分辨率从～78ps降到～64ps. 按照20fb^－1的ψ(3770)数据量进行估算, 在95%置信度下, D⁰-D⁰混合率的上限值可以提高7%左右.     

相对论性核碰撞中K+/π+增强的输运模型解释

提出了一个研究相对论性核碰撞中K⁺/π⁺增强的简单的强子输运模型,指出了核子热运动和多次再散射效应的重要性.考虑了多次再散射,在合理的温度范围内(T～150MeV),可得到与实验相符合的K+/π+比值(～0.20).     

s=29─35GeV e+e－湮没中D±介子的平均多重数

分析了TASSO等5个实验组的数据,并采用最新衰变分支比,得到了s=29-35GeV e⁺e^－湮没中D^*±介子的平均多重数〈D^*++D^*－〉为0.24±0.02.这个结果同在Review of Particle Physics中公布的〈D^*++D^*－〉为0.43±0.07严重不符. 我们认为,我们的结果是可信的.     

Color-Triplet Pseudo-Goldstone Bosons and the HERA High-Q2 Anomalies

We estimate the cpntributions to HERA e^±p deep inelastic scattering process from the color-triplet pseudo-Goldstone bosons appeared in technicolor theory. We find that the F = 0 scalar technicolor leptoquark P₃', the lighter mixed state of charge 2/3 color-triplet pseudo-Goldstone bosons, can provide the required extra contributions to account for the excesses of both neutral and charged current events with very high Q² at HERA simultaneously.     

Signatures of Neutral PG Boson P0a at the Tevatron

In topcolor-assisted technicolor scheme,we calculate the correction of the neutral color octet PG boson P0a to top quark production at the Tevatron.The result is that the PG boson P0a can significantly enhance the top quark production cross section.     

PG玻色子Pa0在Tevatron上的可能物理迹象

在Topcolor-Assisted Technicolor框架下,计算了多标度WTC模型的中性色八重态PG玻色子P0a对top夸克产生截面的修正,结果表明P0a可以增大Tevatron上top夸克的产生截面.     

Production of a neutral scalar associated with a photon at the LHC in the topcolorassisted technicolor model

In the context of the topcolor-assisted technicolor (TC2) model, we consider the production of the neutral scalar S(π_t⁰ or h_t⁰) associated with a photon at the LHC and compare our results with those given by the minimal supersymmetric extension of the Standard Model (MSSM). We find that its production cross section is larger or smaller than that of the scalar particle predicted by the MSSM model, depending on the values of the relevant free parameters.     

The Anomaly Coupling of Axigluon and Technicolor Neutral Pseudo Goldstone Bosons

By gauging the anomaly terms according to the gauge group SU(3)_cl x SU(3)_cr × SU(2)_l × U(l)_Y in the technicolor theory, we obtain various possibld anomaly vertices involving technicolor pseudo Goldstone boson and gauge boson (γ, Z, g, g_A). We estimate the decay rates of g_A → gP⁰, g_A → P_A⁰³γ and g_A → P_A⁰³Z.     

Constraints on Technicolor Models from Inclusive Decay of B Meson

Corrections to the branching ratio BR (B → X_s γ) 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 → X_s γ) for a certain range of parameters.     

Technichiral color and the generation structure

We generalize a recently proposed chiral color model to a technicolor theory. This generalization has two interesting features: (a) The generation number of the ordinary quarks is determined by the technicolor group structure. (b) The technifermion condensates break both the chiral color and the electroweak symmetries. We also consider cases of slowly running coupling for the technicolor interaction.     

Production of a neutral scalar associatedwith a photon at the LHC in the topcolor-assisted technicolor model

In the context of the topcolor-assisted technicolor (TC2) model, we consider the production of the neutral scalar S(π_t⁰ or h_t⁰) associated with a photon at the LHC and compare our results with those given by the minimal supersymmetric extension of the Standard Model (MSSM). We find that its production cross section is larger or smaller than that of the scalar particle predicted by the MSSM model, depending on the values of the relevant free parameters.     

NLO Corrections of HTC Π0 and Π+Π- Pair Production at ILC in TC2 Model

As well known, if the Higgs boson were not observed at LHC, the technicolor model would be the most favorable candidate responsible for the symmetry breaking. To overcome some defects in the previous model, some extended versions have been proposed. In the TC2 model typical signature is existence of heavy H_TC and technipion Π. A direct proof of validity of the model is to produce them at accelerator. Thus we study the production rates of e⁺ e^- → H_TCΠ⁰ and e⁺ e^- → Π⁺ Π^- at ILC in the topcolor-assisted technicolor (TC2) model. In fact, there is a flood of models belonging to new physics, which can result in products withcharacteristics similar to H_TC+Π of the TC2 model. Therefore to distinguish this model from others one may need to investigate some details by calculating the cross section to NLO. We indeed find that the NLO corrections are significant, namely the ratio δ ≡ (σ_NLO- σ_LO)/σ_LO in e⁺ e^- → H_TC Π⁰ exceeds 100% within a plausible parameter space.     

Production of the neutral top-pion πt0 in association with a high-pw jet al the LHC

In the framework of the topcolor-assisted technicolor (TC2) model, we study the production of the neutral top-pion πt0 in association with a high-pT jet al the LHC, which proceeds via the partonic processes gg→πt0g, gq→πt0q, qq→πt0g, gb(b)→πt0b(b), and bb→πt0g. We find that it is very challenging to detect the neutral top-pion πt0 via the process pp→πt0 +jet-t-X→tt +jet + X, while the possible signatures of πt0 might be detected via the process pp→πt0 +jet+X→(tc+tc)+jet+X at the LHC.