Supersymmetric flipped SU(5) revitalized

We describe a simple N = 1 supersymmetric GUT based on the group SU(5)×U(1) which has the following virtues: the gauge group is broken down to the SU(3)_C×SU(2)_L×U(1)_Y of the standard model using just 10, $\text{10}$ Higgs representations, and doublet-triplet mass splitting problem is solved naturally by a very simple missing-partner mechanism. The successful supersymmetric GUT prediction for sin²θ_w can be maintained, whilst there are no fermion mass relations. The gauge group and representation structure of the model may be obtainable from the superstring.     

Symmetry breaking of supersymmetric SU(5)

Numerous inequivalent ground states are shown to exist in the supersymmetric SU(5) model. We derive necessary conditions for an explicit breaking of supersymmetry to yield a potential bounded from below and to select the phenomenologically desired vacuum. These requirements are fulfilled in an example.     

顶超对称夸克与重夸克的束缚态质谱

基于实验尚未完全排除最轻的超对称夸克伴子--标量顶夸克1(1)的寿命可相当长,以至在它产生后衰变之前有机会与通常夸克或胶子形成‘强子'的可能性的这一事实,建立了这一标量顶夸克1(1)和另一重夸克Q()组成的颜色单态束缚态(c1)和(b1)(以及它们反粒子相应的束缚态)的贝特-沙皮特方程,并借助瞬时近似求出了相应束缚态的质谱.     

Spectroscopy for the Bound States of a Top Squark (t) and a Heavy Quark

Based on the possibility that the life time of the lightest top squark 1(1) may be long enough and it may form a bound state with another quark before its decay has not been ruled out yet, we focus on the bound states of the lightest top squark 1(1) and a heavy quark Q(), and establish the Bethe Salpeter equation for the binding systems (c1) and (b1) (or their antiparticles) etc with QCD inspired kernel. We then investigate these systems and give their spectroscopy by means of instantaneous approximation.     

手征SU(3)夸克模型与六夸克态的研究

用手征 SU( 3)夸克模型分析了 ( 0 s) 6组态的六夸克态能量 ,结果表明手征 SU( 3)介子场可以对某些多奇异数的态提供较强的吸引作用 .进一步用共振群方法研究了 ( ΩΩ) 0 + 及 ( ΩΞ) 1+ 等多奇异数系统 ,得到 ( ΩΩ) 0 是一个深度束缚的双重态. An analysis is made for the (0s) 6 six quark cluster states in the chiral SU (3) quark model. The results show that for some multistrangeness states the chiral SU (3) could offer more attraction. Further RGM dynamical calculation of the multistrangeness system (ΩΩ) 0+ and (ΩΞ) 1+ has been done. It shows that (ΩΩ) 0+ is a deeply bound state in the chiral SU (3) quark model.     

手征SU(3)夸克模型的六夸克集团态的研究

用手征SU(3)夸克模型分析了(Os)6组态的六夸克态能量,结果表明手征SU(3)介子场可以对某些高奇异数的态提供较强的吸引作用,这为进一步讨论是否有可能存在窄宽度的六夸克态提供了有用的信息.     

Supersymmetric SU C (4) × SU L (2) × SU R (2) and spontaneous breakdown of symmetries

A supersymmetric version of the left right symmetric partial unification group SU _C (4) × SU _L (2) × SU _R (2) is presented. The spontaneous breakdown of gauge symmetry in a favourable chain of descent has been studied in detail. The mass spectra have been calculated. The method of O’Raifeartaigh has been used to break supersymmetry. The lifting of degeneracy of mass levels between physical multiplets has been shown to occur due to radiative corrections.     

Supersymmetric Quantum Mechanics and SUSY Dependent SU(2) Symmetry for a Spin-1/2 Charged Particle in a Magnetic Field

We find that in a supersymmetric quantum mechanics (SUSY QM) system, in addition to supersymmetric algebra, an associated SU(2) algebra can be obtained by using semiunitary (SUT) operator and projection operator, and the relevant constants of motion can be constructed. Two typical quantum systems are investigated as examples to demonstrate the above finding. The first example is the quantum system of a nonrelativistic charged particle moving in x-y plane and coupled to a magnetic field along z axis. The second example is provided with the Dirac particle in a magnetic field. Similarly there exists an SU_τ(2) \otimes SU_σ(2) symmetry in the context of the relativistic Pauli Hamiltonian squared. We show that there exists also an SU(2) symmetry associated with the supersymmetry of the Dirac particle.     

Light Quark Masses in the Theory with the Dynamical Breaking of Chiral Symmetry

JETP Letters - Mass formulas and decay constants of pseudoscalar π and K mesons have been obtained in the theory with four-quark interactions. To calculate the quark determinant, a Volterra...     

Qq^- Q ^- q＇ States in Chiral SU（3） Quark Model

We study the masses of Qq^- Q ^- q＇ states with J^PC=0^＋＋,1＋＋ and 2^＋＋ in the chiral SU（3）quark model, where Q is the heavy quark （c or b） and q （q＇） is the light quark （u, d or s）. According to our numerical results, it is improbable to make the interpretation of [cn^-C^-n]1＋＋ and [cn^-C^-n]2＋＋ （n = u, d） states as X（3872） and Y（3940）, respectively. However, it is interesting to find the tetraquarks in the bq^-b^-q＇ system.     

An Extended Chiral SU(3) Quark Model

The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiralfields are considered, the phase shifts of 1 So wave are obviously improved.     

Supersymmetric extension of the SU(3)×SU(2)×U(1) model

We describe a class of supersymmetric SU(3)×SU(2)×U(1) models where all quarks and leptons, as well as their scalar partners, get masses through one-loop radiative corrections.     

SU(3)夸克模型中的ΩN束缚态

从夸克–反夸克通过介子场耦合的模型出发研究了(ΩN)LST是否存在束缚态的问题.计算表明当考虑了su(sd)湮没为K介子的机制后,(ΩN)0212是有可能形成结合能较大的束缚态.     

KN Phase Shifts in Chiral SU（3） Quark Model

The isospin I = 0 and I = 1 kaon-nucleon S and P partial waves phase shifts have been studied in the chiral SU(3) quark model by solving a resonating group method equation. When the parameters of the chiral fields are taken in a reasonable region, the numerical results of S-wave are in good agreement with the experimental data, and the P-wave phase shifts can also be explained qualitatively by the calculation of only central force considered.     

KN Phase Shifts in Chiral SU(3) Quark Model

The isospin I = 0 and I = 1 kaon-nucleon S and P partial waves phase shifts have been studied in the chiral SU(3) quark model by solving a resonating group method equation. When the parameters of the chiral fields are taken in a reasonable region, the numerical results of S-wave are in good agreement with the experimental data, and the P-wave phase shifts can also be explained qualitatively by the calculation of only central force considered.     

QQqq Four-Quark Bound States in Chiral SU(3) Quark Model

The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q is the light quark (u, d, or s). We obtain a bound state for the bbnn configuration with quantum number J^P=1⁺,I=0 and for the ccnn (J^P=1⁺,I=0) configuration, which is not bound but slightly above the D^*D^* threshold (n is u or d quark). Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.     

Nuclear Matter in a Chiral SU(3) Quark Mean-Field Model

A quark meson coupling model based on SU(3)_L×SU(3)_R symmetry and scale invariance is proposed. The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite temperature and density. The effective baryon masses, compression modulus and hyperon potentials are all reasonable. The critical temperature of liquid-gas phase transition is also calculated in this model.