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1.
We propose a composite model for quarks and leptons based on an exact SU(3)C × SU(3)H gauge theory and two fundamental J=12 fermions: a charged T-rishon and a neutral V-rishon. Quarks, leptons and W-bosons are SU(3)H-singlet composites of rishons. A dynamically broken effective SU(3)C × SU(2)L × SU(2)R × U(1)B?L gauge theory emerges at the composite level. The theory is “natural”, anomaly free, has no fundamental scalar particles, and describes at least three generations of quarks and leptons.  相似文献   

2.
We analyze proton decays and neutron oscillations in the rishon model. Proton decay is forbidden in lowest order of the compositeness scale ΛH. In a one-generation rishon model, the leading proton decays violate B?L (e.g., p→νπ+). The lifetime is given by τpΛH8/(UR2mp7), where URM(WR) is the mass scale of the right-handed W boson and mp is the proton mass. For UR~500 GeV, the obtained limit for the compositeness scale is ΛH?108 GeV. Neutron oscillations are also proportional to ΛH8 and cannot be detected in the foreseeable future. All of these predictions may depend strongly on the understanding of higher generations of quarks and leptons within the model.  相似文献   

3.
The rishon model is studied in the limit gc → 0, α → 0 when its global flavour symmetry is SU(6) × SU(6) × U(1) analogous to six massless flavour QCD. Recently it was shown that the ad hoc breaking SU(6) × SU(6) → SU(3) × SU(3) allows the anomaly constraint to be satisfied. In this paper this is shown to be but one of several successful patterns of chiral symmetry breaking. The condensates required to perform these breakings are fully discussed. A plausibility argument based on single gauge boson exchange is presented which determines the condensate uniquely to be 〈(vLVL)3〉 corresponding to the original breaking above. The same argument applies to QCD, which is argued to differ in its chiral behaviour due to the large intrinsic masses of the quarks. The implications of the above condensate and pattern of chiral symmetry breaking for the rishon model include the prediction of integer charged colour octet fermions, a naive mass formula me = 2mu ? md, new insight into the parity-violating condensate 〈(vLvL)2(vRvR)〉 and the prediction of 52 new pseudos whose masses are estimated.  相似文献   

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5.
The spin of a free electron is stable but its position is not. Recent quantum information research by G. Svetlichny, J. Tolar, and G. Chadzitaskos have shown that the Feynman position path integral can be mathematically defined as a product of incompatible states; that is, as a product of mutually unbiased bases (MUBs). Since the more common use of MUBs is in finite dimensional Hilbert spaces, this raises the question “what happens when spin path integrals are computed over products of MUBs?” Such an assumption makes spin no longer stable. We show that the usual spin-1/2 is obtained in the long-time limit in three orthogonal solutions that we associate with the three elementary particle generations. We give applications to the masses of the elementary leptons.  相似文献   

6.
We present a QCD-like composite model in which quarks, leptons and technifermions are three-body systems made out of three kinds of massless elementary fermions t, c and w, each carrying technicolor, color and weak gauge interactions, respectively. Discrete symmetries, remnants of the U(1)A of the original lagrangian, are responsible for the masslessness of all the quarks and leptons and give the precise meaning of the generations. The model exhibits three generations for both quarks and leptons. Small but non-zero masses of the quarks and leptons are produced by the technicolor condensate of the composite technifermions, which thereby leads to the non-trivial Cabibbo mixing. Proton decays are all forbidden at the mass scale of the QCD-like theory.  相似文献   

7.
陈凤至  勾亮 《中国物理 C》1995,19(6):513-518
提出了一种定义在10维时空上的SO(17)统一模型,通过相对于陪集空间SU(3)/U(1)×U(1)×Z2的维度退化,得到了具有三代轻费米子的标准模型.  相似文献   

8.
Physics of Atomic Nuclei - CP-symmetry violates in oscillations of neutrinos in vacuum in presence of three generations. In this case there is an inherent complex phase in PMNS-matrix. When any two...  相似文献   

9.
中心对称萘酞菁分子二次谐波产生的实验研究   总被引:2,自引:1,他引:2  
研究了三种萘酞菁化合物LB膜的制备,并通过二次谐波产生的方法研究了单个对称取代的萘酞菁化合物及双(四叔丁基萘酞菁)铒的二阶非线性光学特性,并对它们的产生机理进行了简单的讨论.单个对称取代的萘酞菁化合物,它们的二次谐波产生机制为磁偶极子耦合机制,双(四叔丁基萘酞菁)铒的二阶非线性光学特性起源于电四极子模型,且它的二阶非线性极化率χ(2)(或超极化率β)大于单个萘酞菁化合物.  相似文献   

10.
Resonant light scattering by mesoscale dielectric spheres has received enormous attention and found many interesting applications. The recently emerged field of Mesotronics provides novel opportunities for wavelength-scaled optics and new fundamental aspects are still being uncovered. It has recently been demonstrated that high-order Mie resonances can be excited in homogeneous low-dissipation mesoscale dielectric spheres, leading to the generation of intense magnetic fields. This article describes a simple and effective way to drastically enhance the superresonance effect. Proof-of-principle results for the first time show that yet one more novel phenomenon of increasing the intensity of the magnetic field without changing the resonant Mie size parameter of the sphere by introducing an air cavity. In such a dielectric cenosphere (from two Greek words “kenos”-hollow and “sphaira”-sphere), by correct choice of the air cavity size, it is possible to increase the intensity of the electromagnetic fields at the poles of the sphere by an order of magnitude due to increasing of the amplitude of resonant partial wave coefficient.  相似文献   

11.
张淼  贾焕玉 《中国物理 B》2008,17(2):880-886
根据非Lamb-Dicke近似下激光-离子相互作用动力学规律,讨论了如何利用一系列的激光脉冲来驱动冷离子,从而从运动基态出发获得一系列振动数态的宏观叠加态.具体研究了这些叠加态的Q函数、Wigner函数和它们的非经典特性,如压缩和反群聚效应等.结果表明,合适地调节各个所用激光的脉冲长度,所产生的叠加态能很好地逼近熟知的振动相干态.  相似文献   

12.
张淼  贾焕玉 《物理学报》2008,57(2):880-886
根据非Lamb-Dicke近似下激光-离子相互作用动力学规律,讨论了如何利用一系列的激光脉冲来驱动冷离子,从而从运动基态出发获得一系列振动数态的宏观叠加态.具体研究了这些叠加态的Q函数、Wigner函数和它们的非经典特性,如压缩和反群聚效应等.结果表明,合适地调节各个所用激光的脉冲长度,所产生的叠加态能很好地逼近熟知的振动相干态. 关键词: Lamb-Dicke近似 叠加态 相干态 非经典特性  相似文献   

13.
代丽姣  李洪玉 《物理学报》2014,63(24):243601-243601
采用简化库仑爆炸模型对强激光脉冲照射氘代乙烷团簇发生的库仑爆炸过程进行数值模拟,研究了氘代乙烷团簇爆炸产生的氘核动能、中子产额与团簇尺寸的关系,且与氘代甲烷团簇产生的氘核动能及中子产额进行了比较.研究表明,尺寸为5 nm的氘代乙烷团簇在发生库仑爆炸后氘核的最大动能为20.96 keV,获得的中子产额为6.31×105,比同尺寸氘代甲烷团簇产生的氘核最大动能及中子产额更大.因此相对于氘代甲烷团簇,大尺寸的氘代乙烷团簇更适合作为激光驱动团簇库仑爆炸获得高额中子的靶材,这与报道的实验推论相一致.  相似文献   

14.
The investigative results of modulated pulse output from an LD end-pumped passively Q-switched intracavity-frequency-doubling Nd∶YVO4/KTP laser with Cr4+∶YAG saturable absorber are presented. The numerical stimulations of these modulated pulses are carried out basing on the rate equations. It indicated that the modulations are attribute to the frequency beating of two eigenstates of the resonant polarized modes. The theoretical calculations are in good agreement with the experimental observations.  相似文献   

15.
Laser Compton scattering(LCS) can generate X-rays or y-rays with high brightness and easy controlled polarization by applying high-peak-power laser pulses to relativistic electron bunches.One of the most promising approaches to short pulsed X-ray sources is the laser synchrotron source.It is based on LCS between picoseconds relativistic electron bunches and picoseconds laser pulses.A project of Shanghai laser electron gamma source with LCS method has been proposed on Shanghai synchrotron radiation facility.Before that,a prototype has been developed in the beamline of the linear accelerator at the Shanghai Institute of Applied Physics,Chinese Academy of Sciences.The LCS experiment was carried out by using the 107 MeV,5 Hz,1 ns,0.1 nC electron bunches from the linear accelerator and the 18 ns,10 MW peak power,Nd:YAG laser pulses.In this communication,we describe the details and report the first results of this experiment.  相似文献   

16.
Hybrid dendrimers constitute a unique class of well-defined complex architecture featured with a central domain and bifurcated branches with two different dendritic sequences for their atomic configuration and functional groups at the periphery. This review article pioneers the field of new hybrid dendrimers using different generations by nanoconjugation with metals, carbohydrates, nucleotides, proteins/peptides, carbosilane, urea, silica, stem cells, guanidine, etc. The smart dendrimers contain desirable electrical, magnetic, optical, and biological attributes to increase surface area, monodisperse behavior, dose reduction, dissolution, permeability, long-term stability, and significant decrement in nanotoxicity studies. The higher encapsulation of lipid soluble and insoluble moieties explores an excellent platform for the delivery of drugs (ibuprofen, indomethacin, etc.), nucleic acids (oligonucleotide, siRNA, and aptamer), genetic materials , and chemical diagnostic agents (gadolinium chelates and superparamagnetic iron oxide particles) for imaging. Owing to their flexibility in structural adaptability, different health conditions like glaucoma, inflammation, microbial infection, neurodegenerative problems (Alzheimer's disease and Parkinsonism), and cancer are benefited using such long-lasting drug delivery. Advancements in molecular engineering techniques, 3D printing, artificial intelligence, robotic, green synthesis, and microwave-assisted methods aid in the development of economically reliable and personalized pharmaceutical hybrid dendritic systems resembling antibodies, globular proteins, stem cells, enzymes, and genetic materials.  相似文献   

17.
An exact relation is proven between the two-point correlation function of the classical XY model and the free energy of a step associated with two screw dislocations on a crystal surface described by a solid-on-solid model. This result suggests a way to obtain the XY critical exponent ηc from Monte Carlo studies of the solid-on-solid model.  相似文献   

18.
The investigative results of modulated pulse output from an LD end-pumped passively Q-switched intracavity-frequency-doubling Nd:YVO4/KTP laser with Cr4+:YAG saturable absorber are presented. The numerical stimulations of these modulated pulses are carried out basing on the rate equations. It indicated that the modulations are attribute to the frequency beating of two eigenstates of the resonant polarized modes. The theoretical calculations are in good agreement with the experimental observations.  相似文献   

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