Related papers: Surprises from Quarkonium Decay into Photons
Several topics in QCD are reviewed, including: the light-cone Fock state representation, which encodes the flavor, spin and other quark and gluon correlations of hadrons in the form of universal process-independent amplitudes; the…
The propagation of hard partons through spatially extended matter leads to medium-modifications of their fragmentation pattern. Here, we review the current status of calculations of the corresponding medium-induced gluon radiation, and how…
There is currently enormous interest in the investigation of how hadron properties may be altered by immersion in matter. There is strong evidence of a reduction in the mass of the rho meson from relativistic heavy ion collisions as well as…
I review a number of topics where conventional wisdom in hadron physics has been challenged. For example, hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet…
The complete details of our calculation of the NLO QCD corrections to heavy flavor photo- and hadroproduction with longitudinally polarized initial states are presented. The main motivation for investigating these processes is the…
The development of a Modified Perturbation Theory for QCD, introduced in previous works, is continued. The gluon propagator is modified as consequence of a soft gluon pairs condensate in the vacuum. The modified Feynman rules for $\alpha=1$…
We perform a QCD analysis for the radiative decay of a heavy $^3S_1$ quarkonium into the tensor meson $f_2(1270)$. We make an attempt to separate the nonperturbative effect related to the quarkonium and that related to the tensor meson, the…
The diffractive dissociation of a hadron at high energies, by either Coulomb or Pomeron exchange, has a natural description in QCD as the materialization of the projectile's light-cone wavefunctions; in particular, the diffractive…
We review the physics of quarkonium production at high energy colliders, with a specific emphasis on production $via$ fragmentation. We discuss the fragmentation picture for the production of quarkonia at large-$p_T$ at the Tevatron and…
We investigate the $O(\alpha_s v^2)$ correction to the process of pseudoscalar quarkonium decay to two photons in nonrelativistic QCD (NRQCD) factorization framework. The short-distance coefficient associated with the relative-order $v^2$…
The fragmentation functions for gluons to split into P-wave heavy quarkonium states are calculated to leading order in the QCD coupling constant. Long-distance effects are factored into two nonperturbative parameters: the derivative of the…
The charmless bottom meson decays are systematically investigated based on an approximate six quark operator effective Hamiltonian from perturbative QCD. It is shown that within this framework the naive QCD factorization method provides a…
Quantum Chromodynamics (QCD) exhibits complementary descriptions of hadrons: a rest-frame picture based on confinement, chiral symmetry breaking and interquark forces, and a high-energy light-front picture expressed through parton…
In this contribution we study the photoproduction of quarkonium in coherent proton-proton and nucleus-nucleus interactions at the LHC. The integrated cross sections and rapidity distributions are estimated using the Color Glass Condensate…
We introduce a nonperturbative interaction for light-cone fluctuations containing quarks and gluons. The $\bar qq$ interaction squeezes the transverse size of these fluctuations in the photon and one does not need to simulate this effect…
I briefly review Non-Relativistic QCD and related effective theories, and discuss applications to heavy quarkonium decay, and production in electron-positron colliders.
Toponium production at future hadron colliders is investigated. Perturbative QCD corrections to the production cross section for gluon fusion are calculated as well as the contributions from gluon-quark and quark-antiquark collisions to the…
The near threshold photo or electroproduction of heavy vector quarkonium off the proton is studied in quantum chromodynamics. Similar to the high-energy limit, the production amplitude can be factorized in terms of gluonic Generalized…
We consider the quarkonium diffusion, dissociation and recombination inside quark-gluon plasma. We compute scattering amplitudes in potential nonrelativistic QCD for relevant processes. These processes include the gluon absorption/emission…
We calculate the fragmentation function for a light quark to decay into a lepton pair to leading order in the QCD coupling constant. In the formal definition of the fragmentation function, a QED phase must be included in the eikonal factor…