Research of bb Production in the Topcolor Assisted Technicolor Model

In the framework of topcolor assisted technicolor (TC2) model, we calculate the contributions of cross section from the pseudo Goldstone bosons and new gauge bosons to e⁺e^－ →bb. We find that, within reasonable ranges of the parameters, the corrections arising from technipions and new gauge bosons are negligibly small; and the top pions afford dominate contribution, the maxim cross section corrections can reach 43% with the c.m. energy √s=500GeV; whereas in case of √s=1500GeV, the maxim cross section relative corrections is only 3.1%. It might open a window to detect topcolor assisted technicolor model in the experiment of next generation linear collider.     

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 preudo Goldstone bosons and new gauge bosons to e^ e^-→ttk.We find that for reasonable ranges of the parameters,the preudo Goldstone bosons afford dominate contribution,the correction arising from new gauge bosons is negligibly small,the maximum of the relative corrections is-10% with the center-of-mass energy √s=500GeV;whereas in the case of √s=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.     

Runaway vacuum and supersymmetry

We consider a supersymmetric variant of the vacuum alignment condition. Its consequences in theories with pseudo Goldstone bosons are discussed.     

PGB′s Corrections to Top-Quark Production in Topcolor-assisted Multiscale Technicolor Model

In topcolor-assisted multiscale technicolor (TOPCMTC) model.we calculate the corrections of Pseudo Goldstone bosons (technipions,top-pions)to the cross section of the process qq→tt at the Fermilab Tevatron.Our results show that the corrections mainly come form top pions.With reasonable value of the parameters.the correction can increase the total tt production corss section σtt by as much as 17%.This may provide a window to detect tpo-pions.     

人工色动力学对Wb耦合的修正

考虑了一代人工色（ＯＧＴＣ）模型和ｔｏｐｃｏｌｏｒ援助的多标度人工色（ＴＯＰＣＭＴＣ）模型中的规范玻色子对Ｗｔｂ耦合的贡献。发现对角ＥＴＣ玻色子的交换对Ｗｔｂ耦合没有直接贡献，运用ＬＥＰ给出的Ｒｂ的数值，发现对于一定范围内的参数值来说，ＯＧＴＣ模型中的ＥＴＣ规范玻色子交换和ＴＯＰＣＭＴＣ模型中的ＥＴＣ规范玻色子交换和ｃｏｌｏｒｎ交换对ＣＫＭ矩阵元Ｖｔｂ的贡献都是相当大的，Ｖｔｂ可能被费米实验室ＴｅｖａｔｒｏｎＲｕｎ３探测到。     

Consequences of the non-abelian anomaly in supersymmetric theories

In supersymmetric theories, the anomalous interactions involving the Goldstone supermultiplets are found not to be determined from symmetry considerations alone: they depend also on the dynamical details of the model. The origin of the unexpected results lies in the presence of the massless fermionic superpartners of the Goldstone bosons. For example, the decay π⁰ → γγ is found to be suppressed in supersymmetric QCD (SQCD). Low-energy effective actions with the correct symmetry properties are constructed, taking SQCD as an illustrative example. The axion decay a → γγ in a supersymmetric composite model might be suppressed with the same mechanism that works for π⁰ → γγ in SQCD.     

Spontaneous breaking of scale invariance in a supersymmetric model

The phase structure of a large N, O(N) supersymmetric model in three dimensions is studied. Of special interest is the spontaneous breaking of scale invariance which occurs at a fixed value of the coupling constant, λ₀=λ_c=4π. In this phase the bosons and fermions acquire a mass while a Goldstone boson (dilaton) and Goldstone fermion (“dilatino”) are dynamically generated as massless bound states. The absence of renormalization of the dimensionless coupling constant λ₀ leaves these Goldstone particles massless.     

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.     

在高密度下核物质的色超导性

建立了相变热力学理论和场论的关系. 强调在量子场论中必须引进序参量场， 则相变的讨论就类似于Goldstone bosons 的产生. 如果只讨论一级相变， Goldstone bosons场就足够了; 如果要讨论二级相变， 则必须讨论一系列的场， 这些场构成一个对称群的表示. 另外, 也将这一思想用到色超导中. In this paper we built a relation between the thermodynamical theory of the phase transition and field theory. We emphasized that in the quantum field theory we have to introduce the order parameter fields. Then the discussion of the phase transition is closed to the creation of the Goldstone bosons. If we only discuss the first order transition, the Goldstone bosons fields are sufficient. If we want to discuss the second order transition, we have to discuss a set of fields that constructs a representation of a symmetry group. We also apply this concept to color superconductivity.     

Goldstone boson counting in relativistic systems at finite density

We study the effects of finite chemical potential on the pattern of symmetry breaking within the relativistic linear sigma model. In accordance with previous works we show that type-II Goldstone bosons may appear whose dispersion relation is quadratic in momentum in the long-wavelength limit. We show that their presence is tightly connected with nonzero densities of non-Abelian Noether charges, and formulate a general counting rule for the number of the Goldstone bosons. Working at tree level, we conclude with the discussion of the loop effects. Our results find an application in particular to cold dense quark matter, where a type-II Goldstone boson has been found, e.g., in the phases with kaon condensation.     

On goldstone fields in supersymmetric theories

Some aspects concerning the spontaneous breakdown of global internal symmetries in N = 1 supersymmetric theories are discussed. They can be relevant in the context of supersymmetric preon models. We emphasize the connection of Goldstone dynamics to the linear model. Several statements about the number of Goldstone fields are made. The structure of non-linear lagrangians is discussed. In addition, we consider questions concerning complementarity.     

A scenario for SUSY QCD

The following scenario is proposed for supersymmetric QCD: With massless (s) quarks, there is a continuum of vacua, including one with all global symmetries unbroken; with (s) quarks of mass m, there is a unique vacuum, no Goldstone bosons, but a rich spectrum of scalars and fermions of mass O(m). Consistency with various non-perturbative requirements is exhibited.     

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.     

Vacuum instabilities in models with spontaneous symmetry breaking

Adopting as a reference a simple model with spontaneously broken symmetry we show that the extra massless field present in the three approximation in addition to the true Goldstone bosons may induce, through the radiative corrections to its vacuum expectation value, infrared effects which are not compensable without spoiling the symmetry itself. We further extend the analysis to generic lagrangian field models with spontaneous symmetry breaking and prove that the only constraint to their renormalizability arises from the radiative corrections to the vacuum expectation value of the massless fields, except for the true Goldstone bosons which never induce such pathologies.     

REVIEW OF PARTICLE PHYSICS

The Review summarizes much of particle physics and cosmology.Using data from previous editions,plus 3,283new measurements from 899 papers,we list,evaluate,and average measured properties of gauge bosons and the recently discovered Higgs boson,leptons,quarks,mesons,and baryons.We summarize searches for hypothetical particles such as heavy neutrinos,supersymmetric and technicolor particles,axions,dark photons,etc.All the particle properties and search limits are listed in Summary Tables.We also give numerous tables,figures,formulae,and reviews of topics such as Supersymmetry,Extra Dimensions,Particle Detectors,Probability,and Statistics.Among the 112 reviews are many that are new or heavily revised including those on:Dark Energy,Higgs Boson Physics,Electroweak Model,Neutrino Cross Section Measurements,Monte Carlo Neutrino Generators,Top Quark,Dark Matter,Dynamical Electroweak Symmetry Breaking,Accelerator Physics of Colliders,High-Energy Collider Parameters,Big Bang Nucleosynthesis,Astrophysical Constants and Cosmological Parameters.     

Complete double-projection of light fermion masses in supersymmetric composite models

We present some general classes of supersymmetric models in which the 't Hooft anomaly-matching conditions are precisely satisfied by quasi-Goldstone fermions (QGFs) and hence mass of all the light composite fermions is double-protected by supersymmetry and chiral symmetry. To find this kind of models in an economic way we show that the low-energy spectrum consistent with chiral symmetry is exhausted by QGFs whenever there exists a complementary Higgs picture of the QGF model.     

Corrections to the Zτ +τ− vertex in topcolor-assisted technicolor theory

We calculate the corrections to the Zτ⁺τ^? vertex in the one-family topcolor-assisted technicolor models without exact custodial symmetry contributed from the exchange of extended technicolor (ETC) sideways and diagonal gauge bosons and the topcolor gauge boson Z′. The precise measurements of the τ asymmetry parameter Aτ give strong constraint on the free parameters in the topcolor-assisted technicolor models.     

The SM as the quantum low-energy effective theory of the MSSM

In the framework of the minimal supersymmetric standard model we compute the one-loop effective action for the electroweak bosons obtained after integrating out the different sleptons, squarks, neutralinos and charginos, and present the result in terms of the physical sparticle masses. In addition we study the asymptotic behavior of the two-, three- and four-point Green's functions with external electroweak bosons in the limit where the physical sparticle masses are very large in comparison with the electroweak scale. We find that in this limit all the effects produced by the supersymmetric particles can either be absorbed in the standard model parameters and gauge bosons wave functions, or else they are suppressed by inverse powers of the supersymmetric particle masses. This work, therefore, completes the proof of decoupling of the heavy supersymmetric particles from the standard ones in the electroweak bosons effective action and in the sense of the Appelquist–Carazzone theorem; we started this proof in a previous work. From the point of view of effective field theories this work can be seen as a (partial) proof that the SM can indeed be obtained from the MSSM as the quantum low-energy effective theory of the latter when the SUSY spectra are much heavier than the electroweak scale. Received: 27 March 1999 / Revised version: 7 September 1999 / Published online: 27 January 2000     

Complex-mass renormalization in chiral effective field theory

We consider a low-energy effective field theory of vector mesons and Goldstone bosons using the complex-mass renormalization. As an application we calculate the mass and the width of the ρ meson.