相关论文: Nucleon sea and the five-quark components
It is now widely recognized that a key to unravel the nonperturbative chiral-dynamics of QCD hidden in the deep-inelastic-scattering observables is the flavor structure of sea-quark distributions in the nucleon. We analyze the flavor…
The theoretical foundations of the quantum statistical approach to parton distributions are reviewed together with the phenomenological motivations from a few specific features of Deep Inelastic Scattering data. The chiral properties of QCD…
A physical model is presented for the non-perturbative parton distributions in the nucleon. This is based on quantum fluctuations of the nucleon into baryon-meson pairs convoluted with Gaussian momentum distributions of partons in hadrons.…
We investigate the flavour and quark-antiquark structure of the polarized nucleon by calculating the parton distribution functions of the nucleon sea using the meson cloud model. We find that the SU(2) flavor symmetry in the light antiquark…
SU(2)-flavor-symmetry breaking in antiquark distributions of the nucleon was suggested by the New Muon Collaboration (NMC) in deep inelastic muon scattering. As an independent test, Drell-Yan data for the tungsten target have been used for…
The HERMES collaboration recently reported a reevaluation of the strange-quark parton distribution, $S(x)$, based on kaon production in semi-inclusive deep-inelastic scattering. Two distinct results on $S(x)$ at the $x> 0.1$ region, one…
The sea quark contributions to the nucleon electromagnetic form factors from up, down and strange quarks are studied with the nonlocal chiral effective Lagrangian. Both octet and decuplet intermediate states are included in the one loop…
We studied the statistical model of nucleons consisting of sea having various quark-gluon Fock states in addition to valence quarks. Using statistical consideration and taking 86% of the total Fock states contributing to the low energy…
The flavor structure of the nucleon sea provides unique information to test the statistical parton distributions approach, which imposes strong relations between quark and antiquarks. These properties for unpolarized and helicity…
We have developed a physical model for the non-perturbative x-shape of parton density functions in the proton, based on Gaussian fluctuations in momenta, and quantum fluctuations of the proton into meson-baryon pairs. The model describes…
Probabilities of various Fock states with strange and nonstrange quark-gluon sea contents are calculated to probe the hadronic structure. Particularly for nucleon, we find various contributions to the low energy properties from scalar,…
In a world with two quark flavors and a large number of colors (N_c), the polarized and unpolarized quark distributions in the delta are completely determined by those in the nucleon up to {\cal O}(1/N_c). In particular, we find…
Theoretical predictions are given for the light-flavor sea-quark distributions including the strange quark ones on the basis of the flavor SU(3) version of the chiral quark soliton model. Careful account is taken here of the SU(3) symmetry…
It is generally believed that quarks being confined inside nucleons should make their presence felt explictly in nuclei only at higher energies. However it is shown here that the hole in the centre of $ ^{3}H $, $ ^{3}He $ and $ ^{4}He $,…
We discuss the flavor asymmetry of polarized light antiquarks in the nucleon, $\Delta\bar{u}-\Delta\bar{d}$. We present a determination of this quantity based on two global QCD analyses of experimental data, DSSV08 and NNPDFpol1.1, in which…
We review the recent finding of the two-plateau momentum distribution of sea quarks in deep inelastic scattering off nuclei in the saturation regime. The diffractive plateau which dominates for small $\bp$ measures precisely the momentum…
Distinctions between quark to $\Lambda$ and $\bar\Lambda$ longitudinal spin transfers in the semi-inclusive deep inelastic scattering process were observed by the E665 and COMPASS Collaborations. There are suggestions that the difference…
We demonstrate that to a very good approximation the scale-evolution of the intrinsic heavy quark content of the nucleon is governed by non-singlet evolution equations. This allows us to analyze the intrinsic heavy quark distributions…
We provide a first quantitative indication that the wave function of the proton contains unequal distributions of charm quarks and antiquarks, i.e. a nonvanishing intrinsic valence charm distribution. A significant nonvanishing valence…
We present an analysis of the nucleon strange sea extracted from a global Parton Distribution Function fit including the neutrino and anti-neutrino dimuon data by the CCFR and NuTeV collaborations, the inclusive charged lepton-nucleon Deep…