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1.
Occam’s razor and recent data from CERN on photon-photon interactions favour a highly charged rival to the Standard Model. Either of two recently proposed linear colliders could make decisive tests.  相似文献   

2.
The formalism for a new generation of unquenched quark models for baryons in which the effects of quark?Cantiquark pairs are taken into account in an explicit form via a microscopic, QCD-inspired, quark?Cantiquark creation mechanism, is presented. As an application the quark?Cantiquark contribution to the spin of the proton and the ??+ is discussed. Finally the strangeness radius of the ??+ in the closure limit is calculated.  相似文献   

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In this paper we present a method which may be used to get the nuclear effect functions RυA(xt) and RsA(xt) for valence quark distributions and sea quark distributions in the light of the data of 1-A deep inelastic scattering and nuclear Drell-Yan process. Both the functions may be used to test the theoretical models explaining the nuclear effects. With nuclei Fe, Ca and C as examples, the results are shown.  相似文献   

5.
Using renormalization group and field equation techniques and several smoothness assumptions, we argue the effective charge in an ultraviolet free SU(N) color gauge theory becomes infinite in the infrared limit if the number of quark flavors exceeds 13N4.  相似文献   

6.
Quark masses     
Because of the observed similarity between leptons and quarks, any lepton mass formula can be applied with proper modification to estimate the quark masses. In this work such an application of Rosen's (1978) lepton mass formula is attempted.  相似文献   

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Quark masses     
We review the current information about the eigenvalues of the quark mass matrix. The theoretical problems involved in a determination of the running masses mu, md, ms, mc and mb from experiment are discussed with the aim of getting reliable numerical values equipped with error bars that represent a conservative estimate of remaining uncertainties.  相似文献   

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Quark masses     
In quark gluon theory with very small bare masses, -ψMψ, spontaneous breakdown of chiral symmetry generates sizable masses Mu, Md, Ms, … We find (Mu + Md) /2 ≈ mp/ √6 ≈ 312 MeV, and Ms ≈ 432 MeV. Scalar densities have well determined non-zero vaccum expectations 〈0|ua|0〉 ≡ 〈0|ψ(x) (λa/2)ψ(x)/0〉 ≈ ?π2Ma, i.e〈0? uo/vb0〉 ≈ 8 × 10?3 (GeV)3 at an SU(3) breaking of the vacuum c′ ≡ 〈0|u8|〉/〈0|uo|0〉 ≈ ? 16%  相似文献   

11.
Quark stars     
In a development of the hypothesis of quark regions within massive stars, it is shown that superconductivity may arise in these stars. An analysis is made of the properties of quark atoms.Translated from Izvestiya VUZ. Fizika, No. 8, pp. 39–44, August, 1970.  相似文献   

12.
在夸克质量密度相关模型处理奇异夸克物质滴时 ,会发现其半径随温度增加而变小 .为克服这一困难 ,我们通过使口袋常数 B温度参数化 ,引入了夸克质量密度温度相关模型 .在这一模型中 ,B=B0 [1 - a(T/Tc) +b(T/Tc) 2 ],文章中讨论了参数 a,b的取法. It is found that the radius for a stable strangelet is a decreasing function of temperature in quark mass density- dependent model. To overcome this difficulty, we extend this model to quark mass density- and temperature- dependent model in which the vacuum energy density at zero baryon density limit B depends on temperature. An ansatz B=B 0[1-a(T/T c )+b(T/T c ) 2] is introduced and the regions for the best choice of the parameters are studied.  相似文献   

13.
利用色偶极子模型计算了e+e→h′s轻夸克与重夸克强子事例多重数差别,结果与实验在误差范围内一致.并与微扰QCD模型及朴素模型的结果作了比较.  相似文献   

14.
We propose a physical interpretation of the second level of the combinatorial hierarchy in terms of three quarks, three antiquarks, and the vacuum. This interpretation allows us to introduce a new quantum number, which measures electromagnetic mass splitting of the quarks. We extend our argument by analog to baryons, and find someSU(3) and some new mass formulas for baryons. The generalization of our approach to other hierarchy levels is discussed. We present also an empirical mass formula for baryons, which seems to be loosely connected with the combinatorial hierarchy.  相似文献   

15.
The chiral extension of the minimal standard model makes quarks with two chiralities present parallelly. Some interesting questions, such as the possibility of that the leptons are made of additional leptonic quarks and the proton decay are discussed.  相似文献   

16.
在彩虹近似下用Dyson Schwinger 方程研究了禁闭夸克的传播子, 得到了夸克动力学质量随动量变化的关系, 即得到了从流夸克质量到组分夸克质量的动力学过渡.  相似文献   

17.
We study higher dimensional homogeneous cosmological model in the presence of quark and strange quark matter. The dynamical behavior of the model for the strange quark matter equation of state of the form p = \frac13 (r- 4 Bc)p= \frac{1}{3} (\rho- 4 B_{c}) are studied.  相似文献   

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C P Singh 《Pramana》2000,54(4):561-572
Recent trends in the research of quark gluon plasma (QGP) are surveyed and the current experimental and theoretical status regarding the properties and signals of QGP is reported. We hope that the experiments commencing at relativistic heavy-ion collider (RHIC) in 2000 will provide a glimpse of the QGP formation.  相似文献   

20.
提出了一个由轻子-核深度非弹性散射和核Drell-Yan过程的实验数据得到价夸克分布和海夸克分布的核效应函数RvA(xt)和RsA(xt)的方法. 由这两个函数可以检验解释核效应的理论模型. 以铁核为例求出了RvFe(xt)和Rs(Fe)(xt).  相似文献   

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