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N. P. Zotov

Publications and source records attributed to N. P. Zotov.

At least 73 records · Page 4Linked to original sources
arXiv2004

Heavy quark and quarkonium production at CERN LEP2: k_T-factorization versus data

We present calculations of heavy quark and quarkonium production at CERN LEP2 in the k_T-factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analisys is performed. The unintegrated gluon distribution in the photon is taken from the full CCFM evolution equation. The traditional color-singlet mechanism to describe non-perturbative transition of heavy quark pair into a final quarkonium is used. Our analisys covers polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/Psi production exceed our predictions but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the k_T-factorization formalism.

hep-ph↗
arXiv2003

Study of the Linked Dipole Chain Model in heavy quark production at the Tevatron

We present calculations of charm and beauty production at Tevatron within the framework of kT-factorization, using the unintegrated gluon distributions as obtained from the Linked Dipole Chain model. The analysis covers transverse momentum and rapidity distributions and the azimuthal correlations between b and bbar quarks (or rather muons from their decay) which are powerful tests for the different unintegrated gluon distributions. We compare the theoretical results with recent experimental data taken by D0 and CDF collaborations at the Tevatron Run I and II.

hep-ph↗
arXiv2003

Study of the colour singlet model with k_T-factorization in inclusive J/ψproduction at CERN LEP2

We calculate the cross section and the transverse momentum distribution of inclusive J/ψproduction in γγcollisions at CERN LEP2 within the colour singlet model and the k_T-factorization approach, including both direct and resolved photon contributions. The unintegrated gluon distribution in the photon is determined, using the Blumlein's prescription for unintegrated gluon distribution in a proton. We compare our theoretical predictions with preliminary data taken by the DELPHI collaboration at LEP2. In addition, we present our predictions for the J/ψpolarization properties.

hep-ph↗
arXiv2003

Deep inelastic $J/ψ$ production at HERA in the $k_T$-factorization approach and its consequences for the nonrelativistic QCD

In the framework of the $k_T$-factorization approach, we analyse the inclusive and inelastic production of $J/ψ$ particles in deep inelastic $ep$ scattering. We take into account both colour-singlet and colour-octet production channels. We inspect the sensitivity of theoretical predictions to the choice of model parameters. Our theoretical results agree reasonably well with recent experimental data collected by the collaboration H1 at HERA.

hep-ph↗
arXiv2003

B-meson production in p\bar p collisions at Tevatron with k_T-factorization

In the framework of the k_T-factorization QCD approach we consider the production of b quark pairs in p\bar p collisions at the Fermilab Tevatron. We investigate the dependence of the b quark, B meson and decay muon differential cross sections on the different forms of unintegrated gluon distributions. The analysis also covers the azimuthal correlations between the b and \bar b quarks and their decay muons. Our theoretical results agree well with recent data taken by the D0 and CDF collaborations at Tevatron. Finally, we present our predictions for muon-muon and muon-jet cross sections at the Tevatron and CERN LHC conditions.

hep-ph↗
arXiv2002

Inelastic J/psi production at HERA in the colour singlet model with k_T-factorization

In the framework of k_T-factorization QCD approach and the colour singlet model we consider J/ψinelastic photo- and leptoproduction processes at HERA. We investigate the dependences of the single differential and double differential cross section on different forms of the unintegrated gluon distribution. The z and p_T dependences of the spin aligment parameter αare presented also. Our theoretical predictions agree well with recent data taken by the H1 and ZEUS collaborations at HERA. It is shown that experimental study of the polarization J/ψmesons at low Q^2 < 1 GeV^2 is an additional test of BFKL gluon dynamics.

hep-ph↗
arXiv2002

Heavy Quarks on the Lattice

I review the basic ideas behind lattice QCD calculations that involve charm and bottom quarks. I report on the progress in getting the correct hyperfine splitting in charmonium from lattice QCD. Some of the basic technology behind numerical lattice QCD calculations is explained by studying some specific examples: computation of the charm quark mass, and the calculation of fB.

hep-lat↗
arXiv2002

The structure functions F_2^c and F_L^c in the framework of the k_T factorization

We present the perturbative parts of the structure functions F_2^c and F_L^c for a gluon target having nonzero transverse momentum squared at order α_s. The results of the double convolution (with respect to the Bjorken variable x and the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with HERA experimental data for F_2^c. The contribution from F_L^c structure function ranges 10\div30% of that of F_2^c at the HERA kinematical range.

hep-ph↗
arXiv2002

The contribution of off-shell gluons to the longitudinal structure function F_L

We present results for the structure function F_L for a gluon target having nonzero transverse momentum square at order α_s. The results of double convolution (with respect to Bjorken variable x and the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with recent experimental data for F_L at low x values and with predictions of other approaches.

hep-ph↗
arXiv2002

Heavy Quark Production at the TEVATRON in the Semihard QCD Approach and the Unintegrated Gluon Distribution

Processes of heavy quark production at TEVATRON energies are considered using the semihard (k_T factorization) QCD approach with emphasis of the BFKL dynamics of gluon distributions. We investigate the dependence of the p_T distribution of heavy quark production (presented in the form of integrated cross-sections) on different forms of the unintegrated gluon distribution. The theoretical results are compared with recent D0 and CDF experimental data on beauty production.

hep-ph↗
arXiv2001

The contribution of off-shell gluons to the structure functions F_2^c and F_L^c$ and the unintegrated gluon distributions

We calculate the perturbative parts of the structure functions $F_2^c$ and $F_L^c$ for a gluon target having nonzero transverse momentum squared at order $α_s$. The results of the double convolution (with respect to the Bjorken variable $x_B$ and the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with HERA experimental data for $F_2^c$. The contribution from $F_L^c$ structure function ranges (10-30)% of that of $F_2^c$ at the kinematical range of HERA experiments.

hep-ph↗
arXiv2001

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 $x_γ$, 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 $\J/ψ$ meson spin alignement, which is thought to be a vivid manifestation of gluon off-shellness.

hep-ph↗
arXiv2000

Pomeron intercept from BFKL gluon dynamics in deep inelastic charm production at HERA

In the framework of semihard (k$_T$ factorization) QCD approach, we consider the differential cross sections of $D^{*\pm}$ meson production at HERA. The consideration is based on BFKL and CCFM gluon distributions. We find that in the case of BFKL LO gluon distribution the theoretical results are sensitive to the Pomeron intercept parameter $Δ$. We present a comparison of the theoretical results with available ZEUS experimental data.

hep-ph↗
arXiv2000

Heavy quark photoproduction in the semihard QCD approach and the unintegrated gluon distribution

Processes of heavy quark photoproduction at HERA energies are considered using the semihard (k_T factorization) QCD approach with emphasis of the BFKL dynamics of gluon distributions. We investigate the dependences of the total cross section of heavy quark photoproduction and also p_T, and rapidity distributions on different forms of the unintegrated gluon distribution. We present a comparision of the theoretical results with available H1 and ZEUS experimental data for charm and beauty photoproductions.

hep-ph↗