Related papers: Impact Factors for Reggeon-Gluon Transitions
We investigate the form factors for exclusive semileptonic decays of $B$-meson to $D,~D^*$, based on the parton picture and helped by the results of the HQET. We obtain the numerical results for the slope of the Isgur-Wise function, which…
Generalized parton distributions (GPDs) provide a link between form factors, parton distributions and other observables. I discuss the connection between GPDs and parton distributions as a function of the impact parameter. Since this…
The exact form of the form-factor associated with a meson-photon-photon vertex is not known. Different suggestions exist, based on constraints from QCD and on recent experiments. Four different form-factors are studied in this article. We…
Fourier transform of the generalized parton distributions (GPDs) at zero skewness with respect to the transverse momentum transfer gives the distribution of partons in the impact parameter space. We investigate the GPDs as well as the…
Using an effective field theory (EFT) formalism for forward scattering, we reconsider the factorization of $2\to 2$ scattering amplitudes in the Regge limit. Expanding the amplitude in gauge invariant operators labelled by the number of…
It is pointed out that "the colorless objects" in diffractive lepton-nucleon scattering in the small-$x_B$ region can be probed by measuring the scaled factorial moments of final-state-hadrons and the dependence of their scaling behavior…
Dispersive constraints on the shape of the form factors which describe the exclusive decays B -> D^(*) l nu are derived by fully exploiting spin symmetry in the ground-state doublet of heavy-light mesons. The analysis includes all twenty…
The decays of narrow light vector mesons into pseudoscalar mesons and dileptons are calculated to leading order in a recently proposed scheme which treats pseudoscalar and vector mesons on equal footing. Since all required parameters have…
The electromagnetic form factors of the proton in the time-like region and two-photon annihilations into proton-antiproton are investigated. To calculate these processes at moderately large $s$ we use a variant of the Brodsky-Lepage…
A general discussion is presented of the single logarithmic soft factor that appears in two scale QCD observables in processes involving four partons. We treat it as the ``fifth form factor'', accompanying the four collinear singular…
RHIC data on high-$p_T$ hadron production display strong suppression in a wide rapidity region, indicating strong induced energy loss for both transversally and longitudinally traveling partons. We investigate the interplay of energy loss…
On the received coefficients of the analytical forms for deuteron wave function in coordinate representation in form r^(l+1)*exp(-A*r) for the modern realistic nucleon-nucleon potentials NijmI, NijmII, Nijm93, Reid93 and Argonne v18 are…
The elastic and inelastic collision rates in a gluon gas are calculated. The symmetry factor and the phase space integral are discussed in detail. With a symmetry factor and well constrained phase space, the same result can be obtained as…
The suppression of D mesons in non-central heavy-ion collisions is investigated. The anisotropy in collisions at finite impact parameter leads to an ordering of all-angle, in- and out-of-plane nuclear modification factors due to the…
We discuss the effects of instantons in partially broken gauge groups on the low-energy effective gauge theory. Such effects arise when some of the instantons of the original gauge group G are no longer contained in (or can not be gauge…
It is reported on predictions for the $\pi$-$\gamma$ transition form factor obtained within a perturbative approach which includes transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close…
We perform a quantitative analysis of the nuclear modification factor in deuteron--gold collisions R(dAu) within the Color Glass Condensate approach, and compare our results with the recent data from RHIC experiments. Our model leads to…
Integral kernels describing the pair interaction of reggeized gluons and quarks are reconstructed in terms of conformal symmetric 4-point functions in the transverse plane of impact parameters.
We evaluate the impact factor of the transition gamma* -> rhoT taking into account the twist 3 contributions. We show that a gauge invariant expression is obtained with the help of QCD equations of motion. Our results are free of end-point…
The parton structure of the nucleon and pion is investigated in an exploratory model that allows one to assess whether the dressing of quarks can, by itself, produce realistic gluon contributions to light-cone momentum fractions,…