Progress in Small x Resummation

I review recent theoretical progress in the resummation of small x contributions to the evolution of parton distributions, in view of its potential significance for accurate phenomenology at future colliders. I show that a consistent perturbative resummation of collinear and energy logs is now possible, and necessary if one wishes to use recent NNLO results in the HERA kinematic region.Comment: 8 pages, 6 figures, LaTeX with IJMPA document class, invited plenary talk at the conference on QCD and hadronic physics, Beijing 200

Holographic dark energy linearly interacting with dark matter

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cold dark matter coupled to a modified holographic Ricci dark energy through a general interaction term linear in the energy densities of dark matter and dark energy, the total energy density and its derivative. Using the statistical method of $\chi^2$-function for the Hubble data, we obtain $H_0=73.6$km/sMpc, $\omega_s=-0.842$ for the asymptotic equation of state and $z_{acc}= 0.89$. The estimated values of $\Omega_{c0}$ which fulfill the current observational bounds corresponds to a dark energy density varying in the range 0.25R < \ro_x < 0.27R.Comment: March 2012. 6 pp., 6 figures. Note: To appear in the proceedings of the CosmoSul conference, held in Rio de Janeiro, Brazil, 01-05 august of 201

Small Angle Polarization in High Energy P--P Scattering Through Nonperturbative Chiral Symmetry Breaking

We show that a large anomalous contribution due to nonperturbative instanton-like gluonic field configurations to the axial charge of the proton implies high-energy spin effects in $p-p$ elastic scattering. This is the same mechanism which is responsible for anomalous baryon number violation at high energy in the standard model. We compute the proton polarization due to these effects and we show that it is proportional to the center-of-mass scattering angle with a universal (energy-independent) slope of order unity.Comment: (13 pages, 2 figures

Equilibrium molecular energies used to obtain molecular dissociation energies and heats of formation within the bond-order correlation approach

Ab initio calculations including electron correlation are still extremely costly except for the smallest atoms and molecules. Therefore, our purpose in the present study is to employ a bond-order correlation approach to obtain, via equilibrium molecular energies, molecular dissociation energies and heats of formation for some 20 molecules containing C, H, and O atoms, with a maximum number of electrons around 40. Finally, basis set choice is shown to be important in the proposed procedure to include electron correlation effects in determining thermodynamic properties. With the optimum choice of basis set, the average percentage error for some 20 molecules is approximately 20% for heats of formation. For molecular dissociation energies the average error is much smaller: ~0.4.Comment: Mol. Phys., to be publishe