On the Behavior of F2 and its Logarithmic Slopes

It is shown that the CKMT model for the nucleon structure function F2, taken as the initial condition for the NLO evolution equations in perturbative QCD, provides a good description of the HERA data when presented in the form of the logarithmic slopes of F2 vs x and Q2 (Caldwell-plot), in the whole available kinematic ranges. Also the results obtained for the behavior of the gluon component of a nucleon are presented.Comment: 16 pages, 10 figure

Elliptic Flow and Fixed p_T Suppression in a Final State Interaction Model

It has been shown that a final state interaction model, used to describe J/psi suppression, can also describe the fixed p_T suppression of the pi^0 (and charged pions) yield at all values of p_T, with a final state interaction cross-section sigma close to one milibarn. We propose an extension of the model to the pion motion in the transverse plane - which introduces a dependence of the suppression on the azimuthal angle theta_R. Using the same value of sigma, we obtain values of the elliptic flow v_2 close to the experimental ones, for all values of p_T, including the soft p_T region.Comment: 21 pages, 6 figure

Diffractive gamma-gamma production at hadron colliders

We compute the cross section for exclusive double-diffractive gamma-gamma production at the Tevatron, $p{\bar p} \to p + \gamma\gamma + {\bar p}$, and the LHC. We evaluate both the gluon-gluon and quark-antiquark t-channel exchange contributions to the process. The observation of exclusive gamma-gamma production at the Tevatron will provide a check on the model predictions, and offer an opportunity to confirm the expectations for exclusive double-diffractive Higgs production at the LHC.Comment: 16 pages, 7 figure

J/psi suppression at SPS and RHIC in the comovers approach

The NA50 collaboration data on the $J/\psi$ suppression are compared with the results obtained in a comovers approach based on the Dual Parton Model (DPM). Predictions for the $J/\psi$ suppression versus the charged multiplicity - measured in the rapidity region of the dimuon trigger - are given for SPS and RHIC energies.Comment: 4 pages, contribution to QM200

Baryon charge transfer and production asymmetry between Lambda^0 and antiLambda^0 in hadron interactions

The predictions were done for asymmetry between production spectra of Lambda^0 and antiLambda^0 at the energy of LHC experiments. The value of A(s) should be situated in the band between two curves that are calculated in Quark-Gluon String Model with two possible values of intercept alpha_{SJ}(0)=0,5 and 0,9. Both curves describe the asymmetries measured at lower energies up to RHIC experiments. The data of H1 experiment can be fitted only with alpha_{SJ}(0)=0,9.Comment: LateX, 7 pages and 2 figures, poster presentation at PANIC'05, Santa Fe, October 200

Some mass relations for mesons and baryons in Regge phenomenology

In the quasilinear Regge trajectory ansatz, some useful linear mass inequalities, quadratic mass inequalities and quadratic mass equalities are derived for mesons and baryons. Based on these relations, mass ranges of some mesons and baryons are given. The masses of bc-bar and ss-bar belonging to the pseudoscalar, vector and tensor meson multiplets are also extracted. The J^P of the baryon Xi_cc(3520) is assigned to be 1/2^+. The numerical values for Regge slopes and intercepts of the 1/2^+ and 3/2^+ SU(4) baryon trajectories are extracted and the masses of the orbital excited baryons lying on the 1/2^+ and 3/2^+ trajectories are estimated. The J^P assignments of baryons Xi_c(2980), Xi_c(3055), Xi_c(3077) and Xi_c(3123) are discussed. The predictions are in reasonable agreement with the existing experimental data and those suggested in many other different approaches. The mass relations and the predictions may be useful for the discovery of the unobserved meson and baryon states and the J^P assignment of these states.Comment: 41 pages, 1 figure, Late

Hunting a light CP-violating Higgs via diffraction at the LHC

We study the central diffractive production of the (three neutral) Higgs bosons, with a rapidity gap on either side, in an MSSM scenario with CP-violation. We consider the bb-bar and tautau-bar decay for the light H_1 boson and the four b-jet final state for the heavy H_2 and H_3 bosons, and discuss the corresponding backgrounds. A direct indication of the existence of CP-violation can come from the observation of either an azimuthal asymmetry in the angular distribution of the tagged forward protons (for the exclusive pp -> p+H+p process) or of a sin(2phi) contribution in the azimuthal correlation between the transverse energy flows in the proton fragmentation regions for the process with the diffractive dissociation of both incoming protons (pp -> X+H+Y). We emphasise the advantage of reactions with the rapidity gaps (that is production by the pomeron-pomeron fusion) to probe CP parity and to determine the quantum numbers of the produced central object.Comment: 11 pages, 3 figure

Can Gluons Trace Baryon Number?

QCD as a gauge non-Abelian theory imposes severe constraints on the structure of the baryon wave function. We point out that, contrary to a widely accepted belief, the traces of baryon number in a high-energy process can reside in a non-perturbative configuration of gluon fields, rather than in the valence quarks. We argue that this conjecture can be tested experimentally, since it can lead to substantial baryon asymmetry in the central rapidity region of ultra-relativistic nucleus-nucleus collisions.Comment: 12 pages, LaTeX, figures available upon reques