相关论文: Sea Contributions and Nucleon Structure
The effects of "quark sea" in determining the flavor structure of the octet baryons have been investigated in the chiral constituent quark model (\chiCQM). The \chiCQM is able to qualitatively generate the requisite amount of quark sea and…
We study the possible contribution of the nucleon's virtual meson cloud to the sea quark distribution as observed in deep inelastic lepton scattering. We adjust the meson-nucleon cut-offs to the large-x tails of the antiquark distributions,…
We give a comprehensive review of concepts and numerical calculations for SU(2) and SU(3) baryonic systems which are considered as many body systems composed of three quarks coupled to a polarized Dirac sea by a Nambu--Jona-Lasinio like…
Sea quark contents of the octet baryons are investigated by employing an extended chiral constituent quark approach, which embodies higher Fock five-quark components in the baryons wave-functions. The well-known flavor asymmetry of the…
Moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon are presented from a preliminary analysis of lattice results using pion masses down to 359 MeV. The…
Strange quark contributions to the proton magnetic moment are estimated from a consideration of baryon magnetic moment sum rules. The environment sensitivity of quark contributions to baryon moments is emphasized. Pion cloud contributions…
I review the constituent contributions to the spin of the proton extracted from recent data at CERN, SLAC and DESY. The valence, sea quark and antiquark spin-weighted distributions are determined separately. The data appear to imply a small…
The effects of nonperturbatively generated ``quark sea'' have been investigated to determine the flavor structure of the octet baryons. The chiral constituent quark model ($\chi$CQM), which is known to provide a satisfactory explanation of…
The intrinsic quark-antiquark pairs generated by the minimal energy nonperturbative meson-baryon fluctuations in the nucleon sea provide a consistent framework for understanding a number of empirical anomalies observed in the deep inelastic…
In this contribution, we discuss the spin and flavor content of the proton in the framework of the unquenched quark model, and address the role of valence and sea quarks in the nucleon.
We calculate the shadowing of sea quarks and gluons and show that the shadowing of gluons is {\it not} simply given by the sea quark shadowing, especially at small $x$. The calculations are done in the lab frame approach by using the…
We analyze the non-perturbative structure of the strange sea of the nucleon within a meson cloud picture. In a low $Q^2$ approach in which the nucleon is viewed as a three valon bound state, we evaluate the probability distribution of an…
The comparison of magnetic moment of neutron and proton enables to outline qualitatively the structure of nucleon by using a model similar to the one suggested by Ida and Kobayashi that "baryons consist of a qq pair (or a diquark) and…
A brief review on some recent progresses in our understanding of multi-quark components in baryons is presented. The multi-quark components in baryons seem to be mainly in colored quark cluster configurations rather than in ``meson cloud''…
Similarities between nuclear structure study with many-body theory approach and nucleon structure calculations with lattice QCD are pointed out. We will give an example of how to obtain the connected sea partons from a combination of the…
Within the framework of the so-called "valon" model, we argue that a substantial part of the nucleon spin, about 40%, is carried by the polarized valence quarks. The remaining is the result of cancellations between gluon polarization and…
A dynamical valence and sea quark mixing model is shown to fit the baryon ground state properties as well as the spin content of the nucleon. The relativistic correction and the $q^3{\leftrightarrow} q^3q\bar{q}$ transition terms induced by…
We define a constituent quark within QCD. It is shown that the spin of such a quark and hence also the spin of the nucleon reduced due to $\bar{q}q$-pairs, in agreement with experiment. A solution to the spin problem is given.
In this contribution, we present the unquenched quark model as an extension of the constituent quark model that includes the effects of sea quarks via a $^{3}P_{0}$ quark-antiquark pair-creation mechanism. Particular attention is paid to…
The Nambu - Jona-Lasinio model in its SU(2) and SU(3) versions with scalar and pseudoscalar coupling are applied to baryons. The parameters of the model are fixed in the meson sector. The baryons arise as a soliton of three valence quarks…