Heavy quark production in the semihard QCD approach at THERA

In the framework of the semihard ($k_T$ factorization) QCD approach, we consider the photoproduction of D* mesons associated with two hadron jets and the D* production in DIS at THERA conditions with the emphasis on the BFKL and CCFM dynamics of gluon distributions. In the photoproduction of D* mesons the attention is focused on the variable $x_\gamma$, which is the fraction of the photon momentum contributed to a pair of jets with largest $p_T$. We show that our theoretical results are sensitive to the BFKL type dynamics which may be investigated at THERA energies. We also discuss possible effect of \J/\psi meson spin alignement, which is thought to be a vivid manifestation of gluon off-shellness.Comment: 9 pages, 3 figures, in "The THERA Book", DESY-LC-REV-2001-06

Prompt charmonia production and polarization at LHC in the NRQCD with kt-factorization. Part I: psi(2S) meson

In the framework of kt-factorization approach, the production and polarization of prompt psi(2S) mesons in pp collisions at the LHC energies is studied. Our consideration is based on the non-relativistic QCD formalism for bound states and off-shell amplitudes for hard partonic subprocesses. The transverse momentum dependent (unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with Kimber-Martin-Ryskin prescription. The non-perturbative color-octet matrix elements were first deduced from the fits to the latest CMS data on psi(2S) transverse momentum distributions and then applied to describe the ATLAS and LHCb data on psi(2S) production and polarization at 7 TeV. We perform the estimation of polarization parameters $\lambda_\theta$, $\lambda_\phi$ and $\lambda_{\theta \phi}$ which determine psi(2S) spin density matrix and demonstrate that taking into account the off-shellness of initial gluons in the color-octet contributions leads to unpolarized psi(2S) production at high transverse momenta, that is in qualitative agreement with the LHC data.Comment: 19 pages, 8 figures. arXiv admin note: text overlap with arXiv:1108.285

TMD PDFs in Drell-Yan lepton pair production at LHC

We consider the transverse momentum dependent (TMD) quark densities of the proton which are very important ingredients for unpolarized Drell-Yan (DY) lepton pair production. We calculate the TMD sea quark density as a convolution of the Catani-Ciafaloni-Fiorani-Marchesini (CCFM)-evolved gluon distribution and the TMD gluon-to-quark splitting function. Based on the ${\cal O}(\alpha^2)$ production amplitude $q^* + \bar q^* \to Z/\gamma^* \to l^+ + l^-$, calculated by taking into account the effective $q^*\bar q^* Z/\gamma^*$ - vertex, we analyze the distributions on the dilepton invariant mass, transverse momentum and rapidity and specific angular correlations between the produced leptons as measured by the CMS, ATLAS and LHCb collaborations. We briefly duscuss also the process of assiciated lepton pair and jet production in $pp$ collisions at the LHC.Comment: Talk presented at International Workshop on Diffraction in High-Energy Physics, Diffraction-201