arXiv subjects
Publications and source records attributed to V. A. Saleev.
In the framework of the leading order of perturbative QCD and the nonrelativistic quark-diquark model of baryons we have obtained fragmentation function for c-quark to split into Omega_{ccc} baryon. It is shown that at LHC one can expect 3.5 10^3 events with Omega_{ccc} at p_t>5 GeV/c and -1<y<1 per year.
We consider the production of ultrarelativistic parapositronium and orthopositronium atoms in collisions of high energy electrons with laser photons. Our results demonstrate the opportunity of intensive positronium beam formation with Lorentz-factor 10^6 using laser beam conversion on high energy electrons at the future Electron Linear Accelerators.
In the framework of the perturbative QCD and the diquark model of baryons we have obtained the fragmentation functions for heavy quark that split into polarized Lambda_b baryons. We predict the longitudinal polarization asymmetry for the prompt Lambda_b produced in electron-positron annihilation at the Z resonance and estimate the spin-1/2 and spin-3/2 beauty baryon production rate.
In the framework of the nonrelativistic diquark model of the heavy baryons and the perturbative approach of QCD we predict the value and energy dependence for the total cross section of the Lambda_b- and Sigma_b^* -baryons pair production at the energy range of the KEKB and PEP-II e^+e^- colliders.
We compare our theoretical results for charmed quark and J/Psi - photoproduction cross sections obtained in the semihard approach of QCD with H1 and ZEUS experimental data.
In the framework of the relativistic quasipotential quark model the mass spectrum of baryons with two heavy quarks is calculated. The quasipotentials for interactions of two quarks and of a quark with a scalar and axial vector diquark are evaluated. The bound state masses of baryons with $J^P=\frac{1}{2}^+, \frac{3}{2}^+$ are computed.
In the framework of the nonrelativistic QCD and a quark-diquark model of baryons we have obtained the fragmentation functions for heavy quark to split into spin-1/2 and spin-3/2 double heavy baryons. It was predicted the production rates as well as the shape of the energy spectra for the $cc-$ and $bc-$baryons in the region of $Z^o$ peak at LEP collider.
Based on photon structure function formalism we have calculated $B_c(B_c^{*})$ meson production cross section in $γγ$ collisions via partonic subprocess $cγ\to B_c(B_c^{*}) b$. It was shown that this approach gives the same results for $B_c^*(B_c)$ meson cross sections as the direct leading order QCD calculation of the subprocess $γγ\to B_c(B_c^{*})b\bar c$ at small energy. Howere, opposite to the direct QCD calculation we have obtained the increase of the $B_c(B_c^{*})$ meson cross section at large energies. We have found also additional contribution to the $B_c$ meson production via the nonperturbative fluctuations $γ\leftrightarrow J/ψ$.
We calculate fragmentation functions for a b-quark to fragment into color-singlet P-wave bound states $\bar c b$ in the Heavy Quark Effective Theory with the exact account of $O(1/m_b)$ corrections. We demonstrate an agreement of the obtained results with the corresponding calculations carried out in quantum chromodynamics.
Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. Virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small $x$ have been taken into account. The total cross sections, rapidity and $p_{\bot}$ distributions of the charm and beauty quark photoproduction have been calculated. The results are compared with ZEUS experimental data for charm photoproduction cross section.
A study of the $J/ψ$-meson production at large transverse momentum in high energy $γp$ collisions via the charm quark excitation in a photon is presented. Based on perturbative QCD and the nonrelativistic quark model, our calculation demonstrates that the charm content of a photon may be very important for the $J/ψ$ photoproduction at the large transverse momentum. It is shown that at HERA energies $J/ψ$ production via the subprocess $cg\to J/\si c$ dominates over the resolved photon contribution via the subprocess $gg\to J/ψg$ at $p_{\bot}>3$ GeV/c and over the direct photon-gluon fusion contribution at $p_{bot}>10$ GeV/c.
Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small $x$ have been taken into account. The total cross sections, rapidity and $p_{\bot}$ distributions of the charm and beauty quark photoproduction have been calculated. We obtained the some differences between the predictions of the standard parton model and the semihard approach used here.
The decay widths of S-wave quarkonia ($\etc,\etb\to \gg{~~and~~} \J,\U\to\ee$) are calculated on the basis of a quasipotential approach. The nontrivial dependence on relative quark motion of decay amplitude is taken into consideration via quarkonium wave function. It is shown that relativistic corrections may be large (10-50 %) and comparable with QCD corrections.
We present the results of a calculation of the intrinsic charm quark contribution to $J/ψ$ plus open charm associated production at large transverse momentum in hadron collisions at high energies. It is shown that the value of the cross section for such process and its energy dependence are significantly determined by the choice of charm quark distribution function. We find that intrinsic charm contribution to inclusive $J/ψ$ hadroproduction is about 1\% of the total contribution of all mechanisms.
Based on a perturbative theory of quantum chromodynamics and non-relativistic quark model, associated $J/ψ$ plus open charm photoproduction on charm quarks in a proton via partonic subprocess $γc\to J/ψc$ is discussed. It is shown that the value and energy dependence of the cross section for such process remarkably depends on the choice of charm distribution function in a proton. In the region of small $z=E_J/E_γ<0.2$ the contribution of the $γc\to J/ψc$ subprocess in the inelastic $J/ψ$ photoproduction spectra is larger than the contribution of the photon-gluon fusion subprocess. At the energy range of HERA collider intrinsic charm contribution in the total inclusive $J/ψ$ photoproduction cross section may be equal to 4\% of the dominant contribution of photon-gluon fusion mechanism.