We study weighted azimuthal single spin asymmetries in hadron-hadron scattering using the diagrammatic approach at leading order and assuming factorization. The effects of the intrinsic transverse momenta of the partons are taken into account. We show that the way in which T -odd functions, such as the Sivers function, appear in these processes does not merely involve a sign flip when compared ...

We examine the effect of multiple scattering on large transverse momentum reactions in a simple hard scattering model. It is shown that the measured A dependence can be explained under assumptions on the hard scattering component, which are consistent with experiment. We comment on the effect of Fermi motion. (Submitted to Phys. Rev. ) *Work supported by the U. S. Energy Research & Development ...

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 densities with the perturbatively calculable hard-scattering amplitudes. We derive a complete set of hard-scattering amplitudes at next-to-leading order (NL...

The process of exclusive heavy vector meson photoproduction, γp → V p, is studied in the framework of QCD factorization. The mass of the produced meson, V = Υ or J/Ψ, provides a hard scale for the process. We demonstrate, that in the heavy quark limit and at the one-loop order in perturbation theory, the amplitude factorizes in a convolution of a perturbatively calculable hard-scattering amplit...

We present calculation of the next-to-leading corrections to the hard coefficient functions which appear in the description of nonleptonic B-decays in the factorization approach. These corrections, together with radiative corrections to the jet function, represent the full next-to-leading contribution to the hard spectator scattering term in the decay amplitudes. Using obtained analytical resul...

We have reanalysed the ASCA X-ray spectrum of the bright symbiotic star CH Cyg, which exhibits apparently distinct hard and soft X-ray components. Our analysis demonstrates that the soft X-ray emission can be interpreted as scattering of the hard X-ray component in a photo-ionised medium surrounding the white dwarf. This is in contrast to previous analyses in which the soft X-ray emission was f...

Logarithmically enhanced effects due to radiation of soft gluons at large angles in 2 → 2 QCD scattering processes are treated in terms of the ”fifth form factor” that accompanies the four collinear singular Sudakov form factors attached to incoming and outgoing hard partons. Unexpected symmetry under exchange of internal and external variables of the problem is pointed out for the anomalous di...

A brief overview of direct-photon measurements in ultra-relativistic nucleus-nucleus collisions is given. The results for Pb+Pb collisions at √ sNN = 17.3 GeV and for Au+Au collisions at √ sNN = 200 GeV are compared to estimates of the direct-photon yield from hard scattering. Both results leave room for a significant thermal photon component. A description purely based on hard scattering proce...

Modified Rayleigh conjecture (MRC) in scattering theory is proposed and justified. MRC allows one to develop numerical algorithms for solving direct scattering problems related to acoustic wave scattering by soft and hard obstacles of arbitrary shapes. It gives an error estimate for solving the direct scattering problem. It suggests a numerical method for finding the shape of a star-shaped obst...