IMPROVED STATISTICAL QCD MODEL FOR THE QUARK CONTENT OF THE NUCLEON

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1697-1701 ◽  
Author(s):  
C. MÍREZ ◽  
L. TOMIO ◽  
L. A. TREVISAN ◽  
T. FREDERICO
Keyword(s):  
Quark Model ◽  
Energy Levels ◽  
Structure Functions ◽  
Confining Potential ◽  
Difference Formula ◽  
Quark Content

The neutron-to-proton ratio of the structure functions, [Formula: see text], as well as the corresponding difference [Formula: see text] are obtained within a statistical quark model for the nucleon, where the quark energy levels are given by a central linear confining potential.

Quark model calculations of nucleon structure functions

1983 ◽  
Vol 27 (4) ◽  
pp. 1561-1571 ◽  
Author(s):  
L. S. Celenza ◽  
C. M. Shakin
Keyword(s):  
Quark Model ◽  
Structure Functions ◽  
Nucleon Structure ◽  
Model Calculations

Erratum: Quark model calculations of nucleon structure functions

1989 ◽  
Vol 39 (6) ◽  
pp. 2477-2477 ◽  
Author(s):  
L. S. Celenza ◽  
C. M. Shakin
Keyword(s):  
Quark Model ◽  
Structure Functions ◽  
Nucleon Structure ◽  
Model Calculations

3He and 3H polarized structure functions, using the constituent quark model

2009 ◽  
Vol 831 (3-4) ◽  
pp. 243-262 ◽  
Author(s):  
M.M. Yazdanpanah ◽  
A. Mirjalili ◽  
S. Atashbar Tehrani ◽  
F. Taghavi-Shahri
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Structure Functions ◽  
Constituent Quark Model

scholarly journals MASSES OF LIGHT MESONS IN THE RELATIVISTIC QUARK MODEL

2005 ◽  
Vol 20 (25) ◽  
pp. 1887-1893 ◽  
Author(s):  
D. EBERT ◽  
R. N. FAUSTOV ◽  
V. O. GALKIN
Keyword(s):  
Quark Model ◽  
Ground State ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Relativistic Quark Model ◽  
S Wave ◽  
Confining Potential ◽  
Relativistic Formula ◽  
The Masses ◽  
S Quarks

The masses of the S-wave mesons consisting of the light (u, d, s) quarks are calculated within the constituent quark model. The relativistic Schrödinger-like equation with a confining potential is numerically solved for the complete relativistic [Formula: see text] potential including both spin-independent and spin-dependent terms. The obtained masses of the ground state π, ρ, K, K* and ϕ mesons and their first radial excitations are in a reasonably good overall agreement with experimental data.

SPIN STRUCTURE FUNCTIONS OF THE NUCLEON

1992 ◽  
Vol 01 (03) ◽  
pp. 505-524 ◽  
Author(s):  
ROBERT D. CARLITZ
Keyword(s):  
Quantum Chromodynamics ◽  
Quark Model ◽  
Spin Structure ◽  
Structure Functions ◽  
Running Coupling ◽  
Polarized Protons ◽  
Spin Structure Functions

These lectures discuss the substructure of the nucleon, first on the scale of 1 fermi and then at much shorter distances. We review relevant features of the quark model and introduce Quantum Chromodynamics and the idea of a running coupling. Recent data involving polarized protons is discussed in this framework, and an outlook is presented for future experiments relating to the spin substructure of the nucleon.

scholarly journals MASS SPECTRUM OF THE JP=1/2- AND 3/2- PENTAQUARK ANTIDECUPLETS IN THE PERTURBATIVE CHIRAL QUARK MODEL

2005 ◽  
Vol 14 (07) ◽  
pp. 995-1015 ◽  
Author(s):  
T. INOUE ◽  
V. E. LYUBOVITSKIJ ◽  
TH. GUTSCHE ◽  
AMAND FAESSLER
Keyword(s):  
Mass Spectrum ◽  
Quark Model ◽  
Single Particle ◽  
Ground State ◽  
Bound State ◽  
Wave Functions ◽  
Chiral Quark Model ◽  
Confining Potential ◽  
Full Mass Spectrum ◽  
Basic Configuration

We study the recently discovered Θ+ baryon in the context of the perturbative chiral quark model. The basic configuration of the Θ+ is a pentaquark bound state, where the single particle wave functions are the ground state solutions of a confining potential. We classify the resulting pentaquark multiplets as the JP=1/2- and 3/2- flavor SU (3) antidecuplet. The full mass spectrum of the multiplets is determined by including the meson and gluon cloud contributions, which induce flavor SU (3) breaking. The resulting 3/2- antidecuplet is about 185 MeV heavier than the 1/2- one, mainly because of the semi-perturbative gluon effects. We assign the observed Θ+ baryon as a member of the 1/2- antidecuplet and discuss in particular its relation to the recent experimental signal for a Ξ-- baryon.

scholarly journals Quasi-distribution amplitudes for pion and kaon via the nonlocal chiral-quark model

2017 ◽  
Vol 32 (39) ◽  
pp. 1750218 ◽  
Author(s):  
Seung-il Nam
Keyword(s):  
Quark Model ◽  
Quark Mass ◽  
Mass Difference ◽  
Energy Scale ◽  
Light Front ◽  
Distribution Amplitude ◽  
Chiral Quark Model ◽  
Current Quark Mass ◽  
Difference Formula ◽  
Current Quark

We investigate the pseudoscalar (PS) meson ([Formula: see text] and [Formula: see text]) quasi-distribution amplitude (QDA), which is supposed to be an asymptotic analog to the meson distribution amplitude (DA) [Formula: see text] in the limit of the large longitudinal PS-meson momentum, i.e. [Formula: see text], in the non-perturbative (NP) region. For this purpose, we employ the nonlocal chiral-quark model (NLChQM) in the light-front (LF) formalism with a minimal Fock-state for the mesons [Formula: see text][Formula: see text][Formula: see text] at the low-energy scale parameter of the model [Formula: see text][Formula: see text][Formula: see text][Formula: see text]1 GeV. As a trial, we extract the transverse-momentum distribution amplitude (TMDA) from the light-front wave function (LFWF) within the model, and convert it to QDA with help of the virtuality-distribution amplitude (VDA). By doing that, we derive an analytical expression for the NP QDA with the current-quark mass correction up to [Formula: see text]. Numerically, we confirm that the obtained TMDA reproduces the experimental data for the photon-pion transition form factor [Formula: see text] at the low-[Formula: see text] qualitatively well. We also observe that the obtained QDA approaches to DA as [Formula: see text] increases, showing the symmetric and asymmetric curves with respect to [Formula: see text] for the pion and kaon, respectively, due to the current-quark mass difference [Formula: see text]. Assigning [Formula: see text], the moments [Formula: see text] are computed, using the pion and kaon QDAs, and there appear only a few percent deviations in the moments for [Formula: see text] in comparison to the values calculated directly from DAs. It turns out that the higher moments are more sensitive to the change of [Formula: see text], whereas the lower ones depend less on it.

scholarly journals The charged $Z_c$ and $Z_b$ structures in a constituent quark model approach

2020 ◽  
Author(s):  
Pablo G. Ortega ◽  
Jorge Segovia ◽  
David Rodriguez Entem ◽  
Francisco Fernández
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Heavy Quarks ◽  
Coupled Channels ◽  
Wide Range ◽  
Quark Content ◽  
Model Approach

The nature of the recently discovered Z_cZc and Z_bZb structures is intriguing. Their charge forces its minimal quark content to be Q\bar Q q\bar qQQ‾qq‾ (where Q=\{c,b\}Q={c,b} and q=\{u,d\}q={u,d}). In this work we perform a molecular coupled-channels calculation of the I^G(J^{PC})=1^+(1^{+-})IG(JPC)=1+(1+−) charm and bottom sectors in the framework of a constituent quark model which satisfactorily describes a wide range of properties of (non-)conventional hadrons containing heavy quarks. All the relevant channels are included for each sector, i.e.: The D^{(\ast)}\bar D^{\ast}+h.c.D(*)D‾*+h.c., \pi J/\psiπJ/ψ and \rho\eta_cρηc channels for the Z_cZc and B^{(\ast)}B^{\ast}B(*)B* and \Upsilon(nS)\piΥ(nS)π (n=1,2,3n=1,2,3) channels for the Z_bZb analysis. Possible structures of these resonances will be discussed.

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