相关论文: Surprises from Quarkonium Decay into Photons
We review the current status of lattice QCD studies of the nucleon system. In particular, we focus on the determination of the shape of the nucleon by probing its wave function as well as by evaluating the N to Delta transition form…
Theoretical understanding of the observed jet quenching measurements at RHIC and LHC is challenging in QCD because it requires understanding of parton to hadron fragmentation function in non-equilibrium QCD. In this paper, by using…
An effective, low-energy, field theory of s-wave quarkonia, constituent heavy quarks, and gluons is constructed which is manifestly gauge invariant. The interaction Lagrangian has the form of a twist expansion, as typically encountered in…
Inspired by the recent measurements of the $\eta_c$ meson production at LHC, we investigate the relativistic correction effect for the fragmentation function of the gluon into $\eta_c$, which constitutes the crucial nonperturbative elements…
The theoretical description of photon production at particle colliders combines direct photon radiation and fragmentation processes, which can not be separated from each other for definitions of photon isolation used in experimental…
We study the decay processes of $B\rightarrow \rho\eta$, $\rho\eta^{\prime}$ in the perturbative quantum chromodynamics (QCD) approach with a few improvements incorporated in it, where the contributions with large momentum transfer are…
The most significant experimental results on hadron spectra at large transverse momentum available at the time of Quark Matter 2004 conference are reviewed. Emphasis is put on those measurements that provide insights on the properties of…
Quantum chromodynamics (QCD) is the theory of strong interactions of quarks and gluons collectively called partons, the basic constituents of all nuclear matter. Its non-abelian character manifests in nature in the form of two remarkable…
A brief overview of properties of the model of quantized fragmentation of a helical QCD string is followed by the discussion of colour reconnection models and of the ways to reproduce the evolution of the average transverse momentum in…
The photon structure function is a useful testing ground for QCD. It is perturbatively computable apart from a contribution from what is usually called the hadronic component of the photon. There have been many proposals for this…
The extension of the factorization theorems of perturbative QCD to power corrections associated with re-scattering in nuclear collisions is reviewed. The importance of hadron-nucleus collisions is discussed.
We review the recent theoretical progress in heavy quarkonium spectroscopy within the boundstate theory based on perturbative QCD. New microscopic pictures of the heavy quarkonium systems are obtained.
The high energy two-body photodisintegration of the deuteron is an ideal reaction for the identification of quark effects in the nuclei. In particular, the study of this reaction in the few GeV region can clarify the transition from the…
Including corrections of order $O(m_{K^*}/m_B)$, we present an analysis of photonic penguin contributions to the decay $B\to K^* \gamma$ in the perturbative QCD framework. Employing several models of the meson wave functions, we demonstrate…
Following the operator definition of the fragmentation function developed by Collins and Soper, we compute the gluon-to-$h_c$ fragmentation function at the lowest order in the velocity expansion in NRQCD factorization approach. Utilizing…
In this work we study the radiative decays of $B\to \rho (\omega)\gamma$ processes in the modified perturbative QCD approach, where the transverse momenta of the quark and gluons envolved in the interaction process are kept, and the Sudakov…
The perturbative QCD fragmentation functions for a heavy quark to fragment into heavy-light mesons are studied in the heavy-quark limit. The fragmentation functions for S-wave pseudoscalar and vector mesons are calculated to next-to-leading…
I review the status of the modern theoretical approach to weak decays of heavy flavor hadrons based on the 1/m_Q expansion in QCD. The qualitative features are explained and the subtleties in simultaneously incorporating perturbative and…
In these proceedings, I shall review the basic concepts of perturbative QCD in its high-energy limit. I shall concentrate on the approach to the unitarity limit, usually referred to as saturation, as well as on the gluon-number fluctuations…
We investigate the effects of gluon number fluctuations on the total $\gamma\gamma$, $\gamma^*\gamma^*$ cross sections and the photon structure function $F_2^\gamma(x,Q^2)$. Considering a model which relates the dipole-dipole and…