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用孤粒子袋模型计算强子的静态物理性质 总被引:1,自引:1,他引:0
本文在平均场近似下,对孤粒子袋模型作了较详细的数值解,计算了强子静态物理性质.特点是考虑了夸克质量和质心修正后,明显改善gA/gV值,并且,强子质量、均方根电荷半径和磁矩等均与实验值基本相符.初步导出d夸克和u夸克间的质量差. 相似文献
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利用重夸克等数理论,对重味强子Qq、QQq和Qqq以及四夸克态QQqq的质量谱进行了系统定性的研究,并与势模型对QQqq的计算结果进行了比较. 相似文献
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提出一种新的包含三代已知轻子与夸克的SU(5)大统—模型.按本模型,强子可看作由夸克形成的非拓扑孤粒子;轻子与夸克本质上是相同的,它们之间的差别是由对称性自发破缺造成的;在强子内部,夸克质量很小,其性质与已知夸克相同;在强子外部,夸克的性质与已知轻子相同,只是质量很重,并将很快衰变.本文除了定义严格守恒的电荷Q0、费米子数F0外,还在孤粒子内部定义了近似守恒的内色荷、内电荷、内费米子数.已知SU(5)大统—模型的(L-B)守恒相应于本模型的F0守恒. 相似文献
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提出一种新的包含三代已知轻子与夸克的SU(5)大统—模型.按本模型,强子可看作由夸克形成的非拓扑孤粒子;轻子与夸克本质上是相同的,它们之间的差别是由对称性自发破缺造成的;在强子内部,夸克质量很小,其性质与已知夸克相同;在强子外部,夸克的性质与已知轻子相同,只是质量很重,并将很快衰变.本文除了定义严格守恒的电荷Q0、费米子数F0外,还在孤粒子内部定义了近似守恒的内色荷、内电荷、内费米子数.已知SU(5)大统—模型的(L-B)守恒相应于本模型的F0守恒。 相似文献
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We use multispeckle dynamic light scattering to measure the dynamic structure factor, f(q,tau), of gels formed by aggregation of colloids. Although the gel is an elastic solid, f(q,tau) nearly completely decays on long time scales, with an unusual form, f(q, tau) approximately exp{-(tau/tau(f))(mu)}, with mu approximately 1.5 and with tau(f) proportional variant q(-1). A model for restructuring of the gel with aging correctly accounts for this behavior. Aging leads to a dramatic increase in tau(f); however, all data can be scaled on a single master curve, with tau(f) asymptotically growing linearly with age. This behavior is strikingly similar to that predicted for aging in disordered glassy systems, offering convincing proof of the universality of these concepts. 相似文献
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Thresholds for discrimination between pure and tempered musical intervals consisting of simultaneous complex tones (fundamental frequencies f1 and f2) were investigated. For these tones the main clue for the discrimination of pure intervals (f1:f2 = p:q; p and q small integers) from moderately tempered intervals (f1:f2 approximately p:q) is absence versus presence of beats. The strength of the beats (level difference between envelope maximum and minimum or level-variation depth D) was manipulated by introduction of differences in level (delta L) between the two tones. In each of three experiments the discrimination thresholds (DTs) were determined for 13 intervals with different values for p and/or q. Experiment 1 showed that there is a simple relation between frequency-ratio complexity and discriminability: DTs gradually increased (smaller values of delta L) with increasing p + q. Experiment 2, in which tones with harmonics of equal amplitude were used, indicated that level of the interfering harmonics was not responsible for the relation between DT and p + q. Yet, Experiment 3, in which the spectral content of the tones was varied, clearly showed that for all intervals DT had been determined by the interference between nearly coinciding harmonics. Detailed analysis of the results revealed that the relation between DT and ratio complexity might have been the result of masking. 相似文献
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We study the Kolmogorov-Johnson-Mehl-Avrami theory of phase conversion in finite volumes. For the conversion time we find the relationship tau(con)=tau(nu)[1+f(d)(q)]. Here d is the space dimension, tau(nu) the nucleation time in the volume V, and f(d)(q) a scaling function. Its dimensionless argument is q=tau(ex)/tau(nu), where tau(ex) is an expansion time, defined to be proportional to the diameter of the volume divided by expansion speed. We calculate f(d)(q) in one, two, and three dimensions. The often considered limits of phase conversion via either nucleation or spinodal decomposition are found to be volume-size dependent concepts, governed by simple power laws for f(d)(q). 相似文献
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We analyze the contribution from excitation of the \((q\bar q)(f\bar f), (q\bar q)g_1 \cdots g_n (f\bar f)\) Fock states of a photon to high-mass diffraction in DIS. We show that the large-Q2 behavior of this contribution can be described by DLLA evolution from the nonperturbative \(f\bar f\) valence state of the pomeron. Although of higher order in pQCD, the new contribution to high-mass diffraction is comparable to that from the excitation of the \(q\bar qg\) Fock state of the photon. 相似文献
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For a Hamiltonian H(q), given in a suitable set of basis states, we construct diabatic states from requiring conservation of their nodal structure. The diabatic states and energies are single-valued functions for an arbitrary number of parameters q equivalent to {q1,q2,...q(f)}. The method is illustrated for nucleons moving in a deformed Woods-Saxon potential. 相似文献
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H. Klein H. Elchner H.J. Helten H. Kretzer K. Prescher H. Stehle W.W. Wohlfarth 《Nuclear Physics A》1973,199(1):169-185
The break-up reaction p0 + d → p1 + p2 + n has been studied at E0 = 16 MeV in kinematically complete p1-p2 coincidence experiments with special regard to n-p final-state interactions (f.s.i.) and p1-p2 quasifree scattering (q.f.s.). The absolute differential cross section has been measured for n-p f.s.i. c.m. production angles from 60° to 140° and for four pairs of angles with strong contributions due to q.f.s. Calculations with separable nucleon-nucleon potentials based on the Faddeev equations are in good agreement with the data obtained. In general, the shape of the experimental differential cross section is well reproduced. Discrepancies of up to 30 % in the worst cases arise between the absolute values of the theoretical predictions and the experimental data. 相似文献
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Bandyopadhyay R Liang D Yardimci H Sessoms DA Borthwick MA Mochrie SG Harden JL Leheny RL 《Physical review letters》2004,93(22):228302
Multispeckle x-ray photon correlation spectroscopy was employed to characterize the slow dynamics of a suspension of highly charged, nanometer-sized disks. At wave vectors q corresponding to interparticle length scales, the dynamic structure factor follows a form f(q,t) approximately exp([-(t/tau)(beta)], where beta approximately 1.5. The relaxation time tau increases with the sample age t(a) approximately as tau approximately t(1.8)(a) and decreases with q as tau approximately q(-1). Such behavior is consistent with models that describe the dynamics in disordered elastic media in terms of strain from random, local structural rearrangements. The measured amplitude of f(q,t) varies with q in a manner that implies caged particle motion. The decrease in the range of this motion and an increase in suspension conductivity with increasing t(a) indicate a growth in interparticle repulsion as the mechanism for internal stress development implied by these models. 相似文献
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In this paper we analyze the transport of passive tracers by deterministic stationary incompressible flows which can be decomposed over an infinite number of spatial scales without separation between them. It appears that a low order dynamical system related to local Peclet numbers can be extracted from these flows and it controls their transport properties. Its analysis shows that these flows are strongly self-averaging and super-diffusive: the delay (r) for any finite number of passive tracers initially close to separate till a distance r is almost surely anomalously fast ( (r) r2–, with > 0). This strong self-averaging property is such that the dissipative power of the flow compensates its convective power at every scale. However as the circulation increases in the eddies the transport behavior of the flow may (discontinuously) bifurcate and become ruled by deterministic chaos: the self-averaging property collapses and advection dominates dissipation. When the flow is anisotropic a new formula describing turbulent conductivity is identified. 相似文献
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In a series of ten papers (see the flow chart at the end of §I), of which this is the first, we prove that the temperature zero renormalized perturbation expansions of a class of interacting many–fermion models in two space dimensions have nonzero radius of convergence. The models have asymmetric Fermi surfaces and short range interactions. One consequence of the convergence of the perturbation expansions is the existence of a discontinuity in the particle number density at the Fermi surface. Here, we present a self contained formulation of our main results and give an overview of the methods used to prove them.Research supported in part by the Natural Sciences and Engineering Research Council of Canada and the Forschungsinstitut für Mathematik, ETH Zürich. 相似文献