相关论文: Photon Distribution Amplitudes in QCD
The high-energy quark-quark scattering amplitude is calculated first in the case of scalar QCD, using Fradkin's approach to derive the scalar quark propagator in an external gluon field and computing it in the eikonal approximation. The…
The magnitude of four independent amplitudes are determined in charged kaon photoproduction in the energy range of 1500 to 2300MeV incident photon. Differential cross section and three polarization parameters are required for such…
In this work, we will evaluate the nucleon helicity flip form factor at the limit of large momentum transfer. Hereby, we will study the exchange of one and two virtual photons separately. For the calculation of the scattering amplitudes and…
The general method for calculation of valence quark distributions in hadrons at intermediate $x$ is presented. The imaginary part of virtual photon forward scattering amplitude on quark current with hadron quantum number is considered in…
We discuss which part of information about hadron structure encoded in the Generalized Parton Distributions (GPDs) [part of total GPD image] can be restored from the known amplitude of a hard exclusive process. The physics content of this…
Parton distribution functions are key quantities for us to understand the hadronic structures in high-energy scattering, but they are difficult to calculate from lattice QCD. Recent years have seen fast development of the large-momentum…
QCD collinear factorization allows coherent hard exclusive reactions to reveal the quark-gluon structure of light nuclei, enabling their 3D tomography. We study elastic form factors and deeply virtual Compton scattering on a helium-4…
We generalize the celebrated heavy quark expansion to nonlocal QCD operators. By taking nonlocal heavy-light current on the light-cone as an example, we confirm that the collinear singularities are common between QCD operator and the…
We present an analysis of twist-2, leading order QCD amplitudes for hard exclusive leptoproduction of mesons in terms of double/nonforward parton distribution functions. After reviewing some general features of nonforward nucleon matrix…
The density matrix is obtained for short-wavelength photons passing through a medium. For sufficiently large thicknesses of a target this matrix is expressed by the forward scattering amplitude of a photon. For multi-GeV photons scattering…
The electromagnetic emissivity from QCD media away from equilibrium is studied in the framework of closed time path thermal field theory. For the dilepton rate a nonequilibrium mesonic medium is considered applying finite temperature…
This talk will explain how ground state matrix elements specifying moments of quark density and spin distributions in the nucleon have been calculated in full QCD, show how physical extrapolation to the chiral limit including the physics of…
The wide-angle photo- and electroproduction of pions is investigated within the handbag mechanism in which the $\gamma^{(*)} N\to \pi N'$ amplitudes factorize into subprocess amplitudes,$\gamma^{(*)} q\to \pi q'$, and form factors…
We evaluate the thermal photon emission rate from a chirally asymmetric quark gluon plasma using the Hard Thermal Loop approximation. The quasiparticle and plasmino modes prevalent at finite temperature split into L and R-modes in the…
We calculate light-cone distribution amplitudes for non-relativistic bound states, including radiative corrections from relativistic gluon exchange to first order in the strong coupling constant. We distinguish between bound states of…
We study the transverse-momentum spectrum of quarkonium production from single light-parton fragmentation mechanism. In the case of semi-inclusive deep inelastic scattering, we observe that there are two possible initiating processes,…
I survey a number of interesting tests of quantum chromodynamics at the amplitude level which can be carried out in electron-positron annihilation and in photon-photon collisions at low energy, including measurements of fundamental…
The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable…
In this report diffractive high energy reactions are discussed in a functional integral approach where hadronic amplitudes are calculated from vacuum expectation values of lightlike Wegner-Wilson loops. In the first part we calculate…
We present a systematic study of the B meson light-cone distribution amplitudes which are relevant for the QCD factorization approach for the exclusive B meson decays. We construct representations for the quark-antiquark distribution…