Related papers: Quark Orbital Angular Momentum in the MIT Bag Mode…
We study the covariant version of the quark-parton model, in which the general rules of the angular momentum composition are accurately taken into account. We demonstrate how these rules affect the relativistic interplay between the quark…
The quark propagator in presence of an arbitrary gluon field is calculated gauge and Lorentz covariantly order by order in terms of powers of gluon field and its derivatives. The result is independent of path connecting ends of propagator…
In the present work, we have studied how the rotation of the QGP medium affects the transport coefficients and observables in heavy ion collisions. For the noncentral collisions, although most of the angular momentum gets carried away by…
The gravitational form factors for a hadron, the form factors for the hadron matrix element of the QCD energy-momentum tensor, not only describe the coupling of the hadron with a graviton, but also serve as unique quantities for describing…
In this work we address several issues associated with orbital angular momentum relevant for leading twist polarized deep inelastic scattering. We present a detailed analysis of the light-front helicity operator (generator of rotations in…
Using a covariant spectator quark model that describes the recent lattice QCD data for the $\Delta$ electromagnetic form factors and all available experimental data on $\gamma N \to \Delta$ transitions, we analyze the charge and magnetic…
We determine within lattice QCD, the nucleon spin carried by valence and sea quarks, and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately…
A previously constructed $T$-matrix approach for studying the quark-gluon plasma (QGP) is improved by incorporating spin-dependent interactions between partons. These interactions arise from the relativistic corrections to the Cornell…
The work proposes a new method for measuring the gluon jet fraction in jet sample produced at the hadron collider. This method uses model quark/gluon templates - distributions of quark and gluon jets over the jet macro parameter. Within the…
The spin and orbital angular momentum carried by different quark flavors in the nucleon are calculated in the SU(3) chiral quark model with symmetry-breaking. The similar calculation is also performed for other octet and decuplet baryons.…
A covariant spectator quark model is applied to study the gamma N -> N*(1535) reaction in the large Q2 region. Starting from the relation between the nucleon and N*(1535) systems, the N*(1535) valence quark wave function is determined…
Using the instanton picture of the QCD vacuum we compute the nucleon $\bar c^Q(t)$ form factor of the quark part of the energy momentum tensor (EMT). This form factor describes the non-conservation of the quark part of EMT and contributes…
The electromagnetic and gravitational form factors of $\Omega^-$, a spin-3/2 hyperon composed of three $s$ quarks, are calculated by using a covariant quark-diquark approach. The model parameters are determined by fitting to the form…
We derive the angular correlation functions between an arbitary number of partons inside a quark or gluon jet emerging from a high energy hard collision. As an application results for the correlation in the relative angle between two…
Using the volume coupling version of the cloudy bag model, the quark-meson coupling model is extended to study the role of pion field and the properties of nuclear matter. The extended model includes the effect of gluon exchange as well as…
It is well known that in gauge theories, the spin (and orbital angular momentum) of gauge particles is not gauge invariant, although the helicity is; neither are the canonical momentum and canonical angular momentum of charged particles.…
One-loop quark contributions to the dimension-four gluon condensate term in the operator product expansion (OPE) of the scalar glueball correlation function are calculated in the MS-bar scheme in the chiral limit of $n_f$ quark flavours.…
We analyse the baryon magnetic moments in a model that relates them to the parton spins $\Delta u$, $\Delta d$, $\Delta s$, and includes a contribution from orbital angular momentum. The specific assumption is the existence of a 3-quark…
A momentum dependent quark mass may be incorporated into a quark model in a manner consistent with dynamically broken chiral symmetry. We use this to study the high $Q^2$ behavior of the vector, axialvector, scalar and pseudoscalar…
The characters of the angular distributions of quark jets and gluon jets with different flavors are carefully studied after introducing the cone angle of jets. The quark jets and gluon jets are identified from the 3-jet events which are…