Local Casimir Energy for a Wedge with circular outer boundary

The local Casimir energy is investigated for a wedge with and without a circular outer boundary due to the confinement of a massless scalar field with general curvature coupling parameter and satisfying the Dirichlet boundary conditions. Regularization procedure is carried out making use of a variant of the generalized Abel-Plana formula, previously established by one of the authors. The surface divergences in the vacuum expectation values of the energy density near the boundaries are considered. The corresponding results can be applied to the cosmic strings.Comment: 11 pages, 4 figures, discussion of surface divergences extended, new 3D plots, references added, accepted for publication in Class. Quantum Gra

Handedness of direct photons

The azimuthal asymmetry of direct photons originating from primary hard scatterings between partons is calculated. This can be accounted for by the inclusion of the color dipole orientation, which is sensitive to the rapid variation of the nuclear profile. To this end we introduce the dipole orientation within the saturation model of Golec-Biernat and W\"usthoff, while preserving all its features at the cross-section level. We show that the direct photon elliptic anisotropy v2 coming from this mechanism changes sign and becomes negative for peripheral collisions, albeit it is quite small for nuclear collisions at the RHIC energy.Comment: 6 pages, 6 figures, Based on talk given by A.H.R. at II LAWHEP, Sao Miguel das Missoes, Brazil, December 3-7, 200

Applied QCD

These lectures stress the theoretical elements that underlie a wide range of phenomenological studies of high-energy QCD, which include both soft and hard processes. After a brief introduction to the basics of QCD, various aspects of QCD-based phenomenology are covered: colour transparency, hadronization of colour charges, Regge phenomenology, parton model, Bjorken scaling and its violation, DGLAP evolution equation, BFKL formalism, GLRMQ evolution equation and saturation. In the last part of the lecture, we employ the lightcone dipole formalism to describe deep inelastic lepton scattering, DrellYan processes, direct photon production, diffraction, quark and gluon shadowing in nuclei, the Cronin effect and nuclear broadening

Hadron multiplicity in pp and AA collisions at LHC from the Color Glass Condensate

We provide quantitative predictions for the rapidity, centrality and energy dependencies of inclusive charged-hadron productions for the forthcoming LHC measurements in nucleus-nucleus collisions based on the idea of gluon saturation in the color-glass condensate framework. Our formulation gives very good descriptions of the first data from the LHC for the inclusive charged-hadron production in proton-proton collisions, the deep inelastic scattering at HERA at small Bjorken-x, and the hadron multiplicities in nucleus-nucleus collisions at RHIC.Comment: 7 pages, 8 figures; v3: minor changes, one reference added, results unchanged, the version to appear in Phys. Rev.

Azimuthal anisotropy of direct photons

The electromagnetic bremsstrahlung produced by a quark interacting with nucleons or nuclei is azimuthally asymmetric. In the light-cone dipole approach this effect is related to the orientation dependent dipole cross section. Such a radiation anisotropy is expected to contribute to the azimuthal asymmetry of direct photons in pA and AA collisions, as well as in DIS and in the production of dileptons.Comment: Equations (23), (26) and the figures are corrected, references added. The version to appear in Phys. Rev.

Comparing AdS/CFT Calculations to HERA F_2 Data

We show that HERA data for the inclusive structure function F_2(x,Q^2) at small Bjorken-x and Q^2 can be reasonably well described by a color-dipole model with an AdS/CFT-inspired dipole-proton cross section. The model contains only three free parameters fitted to data. In our AdS/CFT-based parameterization the saturation scale varies in the range of 1-3 GeV becoming independent of energy/Bjorken-x at very small x. This leads to the prediction of x-independence of the F_2 and F_L structure functions at very small x. We provide predictions for F_2 and F_L in the kinematic regions of future experiments. We discuss the limitations of our approach and its applicability region, and argue that our AdS/CFT-based model of non-perturbative physics could be viewed as complimentary to the perturbative description of data based on saturation/Color Glass Condensate physics.Comment: 23 pages, 10 figures; v3: new plots added showing our model predictions for charm and longitudinal structure functions and photoproduction cross-section, discussion extended. The version to appear in PR