相关论文: QCD Constituent Counting Rules for Neutral Vector …
At high energies, the cross section of a hard exclusive process at finite scattering angle falls off as a negative power of the center-of-mass energy $\sqrt{s}$. If all involved quark-gluon compositions undergo hard momentum transfers, the…
The constituent counting rules, i.e., the scaling behavior of amplitudes (in terms of the number of fundamental constituents) for exclusive processes when high energy scales are present, have been known for decades, and have been borne out…
We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $\Lambda$ and $\Sigma ^{0}$ of the CLAS and SLAC-E84 collaborations, by considering constituent-counting rule…
We explain a method to find internal quark configurations of exotic hadron candidates by using the constituent counting rule. The counting rule was theoretically predicted in perturbative QCD for hard exclusive hadron reactions, and it has…
We propose to use hard exclusive production of an exotic hadron for finding its internal quark-gluon configuration by the constituent-counting rule in perturbative QCD. In particular, the cross section for the exclusive process $\pi^- + p…
In this work, we investigate the exclusive production of particles in scattering processes in the so-called saturation region. Within this scheme the phenomenon of geometric scaling takes place: cross sections are functions only of a…
We show that an endpoint overlap model can explain the scaling laws observed in exclusive hadronic reactions at large momentum transfer. The model assumes one of the valence quarks carries most of the hadron momentum. Hadron form factors…
We provide a universal expression of cross sections for the exclusive vector meson production and Deeply Virtual Compton Scattering (DVCS) in photon-proton and photon-nucleus interactions based on the geometric scaling phenomenon. The…
The exclusive processes are considered, where a point-like source of heavy quark-antiquark pairs $Q \bar Q$, e.g. their electromagnetic current, produces a pair consisting of a heavy quarkoniumlike exotic meson (tetraquark) or baryon…
Rich experimental data accumulated in the past few years in the hadronic $Z^0$ decays allow one to check the quark combinatorics relations for a new type of processes, namely: quark jets in the decays $Z^0 \to q\bar q \to hadrons$. In this…
We compare two widely used approaches to the description of hadron properties: QCD sum rules and constituent quark models. Making use of the dispersion formulation of the quark model, we show that both approaches lead to similar spectral…
The empirical identification of bound states of gluons has remained a central goal of hadron spectroscopy. We suggest an experimentally challenging, but model--independent way to assess which zero charge, isospin-zero mesons have a large…
We investigate the possibility of clarifying internal structure of exotic hadrons by high-energy exclusive reactions. In particular, the constituent-counting rule could be used for determining the internal configuration in large-angle…
Using the QCD Operator Product Expansion, we derive the real part of the transverse and longitudinal vector vector correlation function with the $\rho,\omega$ quantum numbers to leading order in density and in ${\bf q}^2$ at $-\omega^2\to…
We propose a possible scheme for getting the known QCD scaling laws within string theory. In particular, we consider amplitudes for exclusive scattering of hadrons at large momentum transfer, hadronic form factors and distribution…
We study the exclusive production of scalar $S = 0^{++}$ and tensor $T = 2^{++}$ mesons through single-photon annihilation $e^+ e^- \to \gamma^* \to \gamma S(T)$. Using QCD compositeness of the involved hadrons considered as quark-antiquark…
The constituent counting ruling (CCR) has been found to hold for numerous hard, exclusive processes. It predicts the differential cross section at high energies and fixed $\cos \theta_{c.m.}$ should follow $\frac{d \sigma}{dt} \sim…
In ultra-relativistic heavy ion collisions at $\roots\approx200$ GeV, the azimuthal emission anisotropy of hadrons with low and intermediate transverse momentum ($p_T\lesssim 4$ GeV/c) displays an intriguing scaling. In particular, the…
The process of a light neutral vector meson electroproduction is studied in the framework of QCD factorization in which the amplitude factorizes in a convolution of the nonperturbative meson distribution amplitude and the generalized parton…
Hard hadronic exclusive processes are now at the forefront of QCD studies, particularly because of their role in the interpretation of exclusive hadronic B decays. Perturbative QCD and its factorization properties at high momentum transfer…