arXiv subjects
Publications and source records attributed to D. V. Vasin.
We consider charmonium polarization at high-energy hadron collider Tevatron in the framework of the nonrelativistic QCD (NRQCD) and the k_T-factorization approach. The polarization effects are studied for the direct and the prompt production channels. The obtained predictions can be used to test the Regge limit of QCD and the NRQCD formalism.
We study bottomonium hadroproduction in proton-antiproton collisions at the Fermilab Tevatron in the framework of the quasi-multi-Regge kinematics approach and the factorization formalism of non-relativistic QCD at leading order in the strong-coupling constant alpha_s and the relative velocity v of the bound quarks. The transverse-momentum distributions of prompt Upsilon(nS)-meson production measured at the Tevatron are fitted to obtain the non-perturbative long-distance matrix elements for different choices of un-integrated gluon distribution functions of the proton.
We study charmonium production at high-energy colliders (Tevatron, HERA, and LEP2) in the framework of the k_T-factorization approach and the factorization formalism of non-relativistic quantum chromodynamics at leading order in the strong-coupling constant alpha_s and the relative velocity v. The transverse-momentum distributions of direct and prompt J/psi-meson production measured at the Fermilab Tevatron are fitted to obtain the non-perturbative long-distance matrix elements for different choices of unintegrated gluon distribution functions in the proton. Using the matrix elements thus obtained, we predict charmonium production rates in gamma-gamma, gamma-p, and deep-inelastic e-p collisions including the contributions from both direct and resolved photons. The results are compared with the known ones obtained in the conventional parton model and with recent experimental data from HERA and LEP2.
In the framework of the kT-factorization approach we have calculated in the fragmentation model the pT-spectra of B(c) mesons at the energies of the Tevatron and the LHC Colliders and at the large pT domain. We compare the obtained results with the existing experimental data and with the predictions obtained in the collinear parton model.
We compare the predictions of the collinear parton model and the k_T-factorization approach in JΨand D^\star meson photoproduction at HERA energies. It is shown that obtained in the both approaches D^\star meson spectra over p_T and ηas well as JΨmeson p_T- and z-spectra are very different. The predictions obtained in the k_T-factorization approach are agree with the experimental data well. We also predict the nontrivial p_T-dependence of the the spin parameter $α(p_T) in the JΨphotoproduction.
The p_T-spectra for direct J/psi and psi' in hadroproduction at Tevatron energy have been calculated based on NRQCD formalism and fragmentation approximation in the collinear parton model and k_T-factorization approach. We have described the CDF data and obtained a good agreement between the predictions obtained in the parton model and k_T-factorization approach. We performed the calculations using the relevant leading order in alpha_s hard amplitudes and the equal values of the color-octet long-distance matrix elements for the both models.
It is shown that the difference between the c-quark proton structure functions calculated in the k_T-factorization approach using different unintegrated gluon distribution functions is the same order as the difference between results obtained in the parton model and in the k_T-factorization approach.