共查询到20条相似文献,搜索用时 0 毫秒
1.
Kuang Yu-ping 《Frontiers of Physics in China》2006,1(1):19-37
We review the developments of the multipole expansion approach in quantum chromodynamics and its applications to hadronic
transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compared with updated experimental results. 相似文献
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The existing measurements of quarkonium polarization in proton-antiproton and proton-nucleus collisions are puzzling. We highlight issues which are often underestimated in the experimental analyses: the importance of the choice of the experimental acceptance on the comparison between experimental measurements and theoretical calculations. New measurements must provide more detailed information, such that physical conclusions can be derived without relying on model-dependent assumptions. We also describe a frame-invariant formalism which minimizes the dependence of the measurements on the experimental acceptance, facilitates the comparison with theoretical calculations, and probes systematic effects due to experimental biases. 相似文献
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We derive an Abelian-like Ward identity in the color superconducting phase and calculate vertex corrections to the color superconducting gap. Making use of the Ward identity, we show that subleading order contributions to the gap from vertices are absent for gapped excitations. 相似文献
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We derive an Abelian-like Ward identity in the color superconducting phase and calculate vertex corrections to the color superconducting gap. Making use of the Ward identity, we show that subleading order contributions to the gap from vertices are absent for gapped excitations. 相似文献
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Ulf-G. Meissner 《中国物理 C》2010,34(9):1163-1168
Isospin violation is driven through the light quark mass difference and electromagnetic effects.I review recent progress in extracting the light quark mass difference and tests of the chiral dynamics of Quantum Chromodynamics in various reactions involving light as well as heavy quarks. 相似文献
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We propose a better differential method for the computation of the equation of state of QCD from lattice simulations. In contrast
to the earlier differential method, our technique yields positive pressure for all temperatures including the temperatures
in the transition region. Employing it on temporal lattices of 8, 10 and 12 sites and by extrapolating to zero lattice spacing
we obtained the pressure, energy density, entropy density, specific heat and speed of sound in quenched QCD for 0.9 ≤ T/T
c ≤ 3. At high temperatures comparisons of our results are made with those from the dimensional reduction approach and also
with those from a conformal symmetric theory.
相似文献
11.
Ulf-G.Meiner 《中国物理C(英文版)》2010,34(9)
Isospin violation is driven through the light quark mass difference and electromagnetic effects. I review recent progress in extracting the light quark mass difference and tests of the chiral dynamics of Quantum Chromodynamics in various reactions involving light as well as heavy quarks. 相似文献
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The talk summarizes some new results of lattice investigations of QCD at finite temperature. The topics discussed cover the
flavor dependence of the critical temperature and the equation-of-state as well as hadronic correlation functions. 相似文献
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Quarks are proposed to be grouped together to make quark-clusters due to the strong interaction in cold quark matter at a few nuclear densities, because a weakly coupling treatment of the interaction between quarks there would be inadequate. Cold quark matter is then conjectured to be in solid state (i.e., forming a crystal structure) if the inter-cluster potential is deep enough to localize clusters in lattice. Such a solid state of cold quark matter would be very necessary for us to understand different manifestations of pulsar-like compact stars, and could not be ruled by first principles. 相似文献
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Quarks are proposed to be grouped together to make quark-clusters due to the strong interaction in cold quark matter at a few nuclear densities,because a weakly coupling treatment of the interaction between quarks there would be inadequate.Cold quark matter is then conjectured to be in solid state (i.e.,forming a crystal structure) if the inter-cluster potential is deep enough to localize clusters in lattice.Such a solid state of cold quark matter would be very necessary for us to understand different manifestations of pulsar-like compact stars,and could not be ruled by first principles. 相似文献
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介绍了量子场论中基于准势途径的一个相对论夸克模型,并使用这个相对论夸克模型计算了重夸克偶素的质量谱.显示这个相对论夸克模型可较好地拟合实验上肯定的质量谱数据. A relativistic quark model based on the quasipotential approach in quantum field theory is briefly introduced, and by using this model, heavy quarkonium mass spectra are calculated in detail. It is shown that such a model can give results which are in agreement with the observed experimental data on the mass spectra. 相似文献
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For heavy meson systems, we study the heavy quark potential, which emerges from the effective dilaton-gluon coupling inspired from the superstring theory. We put emphasis on the new confinement generating mechanism of this potential through the investigation of the spin-averaged energy levels of the heavy meson systems. By using a unified approach to the solutions of the Schr?dinger and the spinless Salpeter equations, we can examine in a realistic way the effects of using a relativistic kinetic energy. The obtained results agree favourably with other predictions, and the relativistic equation can better account for the observed energy levels. 相似文献
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We study a model of quark confinement defined by the vanishing of colour currents. The model is shown to be equivalent to
quantum chromodynamics and this equivalence is interpreted as due to the compositeness of the colour gluons. The Green’s functions
of the theory are found to contain nontrivial structure only for colour singlet composites which can be identified with hadrons. 相似文献
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Kamal K. Seth 《Pramana》2004,62(3):615-622
A review is presented of the latest developments in the spectroscopy of charmonium. 相似文献
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Rajiv V. Gavai 《Contemporary Physics》2016,57(3):350-365
Strongly interacting matter, which makes up the nuclei of atoms, is described by a theory called quantum chromodynamics (QCD). A critical point in the phase diagram of QCD, if established either theoretically or experimentally, would be as profound a discovery as the familiar gas–liquid critical point discovered in the nineteenth century. Due to the extremely short-lived nature of the concerned phases, novel experimental techniques are needed to search for it. The Relativistic Heavy Ion Collider (RHIC) in USA has an experimental programme which can fit the bill to do so. Theoretical techniques of Lattice QCD, which is QCD defined on a discrete space-time lattice, have provided glimpses into where the QCD critical point may be, and how to search for it in the experimental data. A brief overview of the theoretical and experimental attempts is provided. 相似文献