Importance of sea contribution to nucleons

Physical Review D, 1994

We suggest a general formalism to treat a baryon as a composite system of three quarks and a 'sea'. In this formalism, the sea is a cluster which can consists of gluons and quark-antiquark pairs. The hadron wave function with a sea component is given. The magnetic moments, related sum rules and axial weak coupling constants are obtained. The data seems to favor a vector sea rather than a scalar sea. The quark spin distributions in the nucleon are also discussed.

Proceedings of Sixth International Conference on Quarks and Nuclear Physics — PoS(QNP2012)

We generalize the approach of Brodsky et al. for the intrinsic charm quark distribution in the nucleons to the light-quark sector involving intrinsicū,d, s ands sea quarks. We compare the calculations with the existingd −ū, s +s, andū +d − s −s data. The good agreement between the theory and the data is interpreted as evidence for the existence of the intrinsic light-quark sea in the nucleons. The probabilities for the |uuduū , |uuddd and |uudss Fock states are also extracted.

Journal of Physics: Conference Series, 2015

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.

The European Physical Journal C, 2008

Within a statistical model of linear confined quarks we obtain the flavor asymmetry and corresponding structure function of the nucleon. The model parameters are fixed by the experimental available data. The temperature parameter is adjusted by the Gottfried sum rule violation and the chemical potentials by the corresponding up (u) and down (d) quark normalizations in the nucleon. The light antiquark and quark distributions in the proton, given by d/u, d/u and d − u, as well as the neutron to proton ratio of the structure functions, extracted from the experimental data, are well fitted by the model. As the quarkconfining strengths should be flavor dependent, a mechanism is introduced in the model to adjust the corresponding distribution, in order to improve the comparison obtained for the sea-quark asymmetries in the nucleon with the available experimental analysis.

Modern Physics Letters A, 1998

The spin 1/2 baryons are pictured as a composite system made out of a "core" of three valence quarks (as in the simple quark model) surrounded by a "sea" (of gluon and qq pairs) which is specified by its total quantum numbers. We assume the sea is a SU (3) flavor octet with spin 0 or 1 but no color. This model, considered earlier, is used to obtain simultaneous fits for masses, magnetic moments and G A /G V for semileptonic decays. These fits give predictions for nucleon spin distributions in reasonable agreement with experiment.

Physics Letters B

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0:003 < x < 0 : 7. From these asymmetries and the previously published inclusive spin asymmetries we determine, for the rst time, the x-dependent spin distributions for up and down valence quarks and for non-strange sea quarks. We nd that the rst moments of the valence quark spin distributions are u v = 1 : 01 0:19 0:14 and d v = 0:57 0:22 0:11. The spin distribution function of non-strange sea quarks is consistent with zero over the measured range of x and the rst moment i s u = d = 0 : 02 0:09 0:03.

Nuclear Physics B - Proceedings Supplements, 2010

Effective Quark mass shift, gluonic and pionic effects EFFECTIVE LIGHT QUARK MASS SHIFT The difference between the interaction of u and d quarks is supposed to come from instanton effects, which are flavour-spin dependent [Dorokhov et al, Sov.J.Part.Nucl. 23 (1992) 522].

International Journal of Modern Physics A, 1998

Spin-1/2 baryons are considered as a composite system made out of a "core" of three quarks surrounded by a "sea" (of gluons and qq-pairs) which is specified by its total quantum numbers. Specifically, we assume this sea to be a flavor octet with spin-0 or 1 but no color. We show our model can provide very goods fits to magnetic moments and semileptonic decay data using experimental errors. The predictions for spin distributions are in reasonable agreement with experiment.

International Journal of Modern Physics A, 1997

We treat the baryon as a composite system made out of a "core" of three quarks (as in the standard quark model) surrounded by a "sea" (of gluons and qq-pairs) which is specified by its total quantum numbers like flavor, spin and color. Specifically, we assume the sea to be a flavor octet with spin 0 or

arXiv: High Energy Physics - Phenomenology, 1996

We performed a phenomenological fit in order to get quark parton polarized distributions in the nucleon. All data on inclusive and semi-inclusive spin asymmetries measured on nucleon targets were used. We present the results for the flavour dependence of polarized sea inside a nucleon. An excellent agreement between inclusive and semi-inclusive data on polarized structure functions was found in our model.