Related papers: Quark Distribution Functions in a Diquark Spectato…
We study the relation between the quark distribution function q(x) and the fragmentation function D_q(z) based on a general form D_q(x) = C(z)z^{alpha}q(z) for valence and sea quarks. By adopting two known parametrizations of quark…
Using the criteria of simplicity, positivity, smoothness and process- independence of construction, we find a non-polynomial model for the quark distribution amplitude of the nucleon that is in agreement with QCD sum-rule constraints. This…
We use phenomenological nonlocal Lagrangians, which lead to non trivial forms for the quark propagator, to describe the pion. We define a procedure, based on the Dyson-Schwinger equations, for the calculation of the pion parton…
We present the results of the covariant spectator quark model applied to the nucleon structure function $f(x)$ measured in unpolarized deep inelastic scattering, and the structure functions $g_1(x)$ and $g_2(x)$ measured in deep inelastic…
Diffractive parton distribution functions give the probability to find a parton in a hadron if the hadron is diffractively scattered. We provide an operator definition of these functions and discuss their relation to diffractive deeply…
The role of models in Quantum Chromodynamics is to produce simple physical pictures that connect the phenomenological regularities with the underlying structure. The static properties of hadrons have provided experimental input to define a…
We present a model calculation of T-odd transverse-momentum-dependent distributions of gluons in the nucleon. The model is based on the assumption that a nucleon can emit a gluon, and what remains after the emission is treated as a single…
We compute the leading-twist T-odd quasi-distributions of the proton in a spectator model with scalar and axial-vector diquarks: the quasi Sivers function $\tilde{f}_{1T}^\perp(x, k_T^2; P_z)$ and the quasi Boer-Mulders function…
We apply the quark delocalization and color screening model to nucleon-baryon scattering. A semi-quantitative fit to N-N, N-Lambda and N-Sigma phase shifts and scattering cross sections is obtained without invoking meson exchange. Quarks…
Transverse parton momentum dependent distribution functions (TMDs) of the nucleon are studied in a covariant model, which describes the intrinsic motion of partons in terms of a covariant momentum distribution. The consistency of the…
This paper presents a distributed Koopman operator learning framework for modeling unknown nonlinear dynamics using sequential observations from multiple agents. Each agent estimates a local Koopman approximation based on lifted data and…
A variational study of two-nucleon systems with lattice quantum chromodynamics is performed using a wide range of interpolating operators: dibaryon operators built from products of momentum-projected nucleons, hexaquark operators built from…
Photon distribution amplitudes up to twist four are calculated within the nonlocal chiral quark model with a simple pole ansatz for momentum dependence of the constituent quark mass. Calculations are performed using modified electromagnetic…
The distribution of the spin of the nucleon among its constituents can be parametrized in the form of polarized parton distribution functions for quarks and gluons. Using all available data on the polarized structure function $g_1(x,Q^2)$,…
In the quantum statistical parton distributions approach proposed more than one decade ago to describe the parton structure, new properties are now understood, in particular, the relation between quarks and antiquarks which leads to very…
A low mass single diffraction dissociation mode based on the quark-diquark representation of hadron-nucleon interaction is proposed. The mass spectra of nucleon-pion system are compared with experimental data and predictions of other…
I discuss the problem of computing the structure functions for very heavy nuclei at small Bjorken x. The approximations used in this description are physically motivated, and recent computations reviewed.
We compute quark structure functions and the intrinsic Fock space distribution of sea quarks in a hadron wavefunction at small x. The computation is performed in an effective theory at small x where the gluon field is treated classically.…
Inclusive and diffractive structure functions for electron-proton scattering are calculated in a semiclassical approach at large momentum transfer $Q^2$ and small values of the scaling variable $x$. The basic process is the production of a…
Valence double parton distribution functions of the nucleon are evaluated in the framework of a simple model, where the conservation of the longitudinal momentum is taken into account. The leading-order DGLAP QCD evolution from the low…