SearcharxivSearch

arXiv subjects

Olga Piskounova

Publications and source records attributed to Olga Piskounova.

3 recordsLinked to original sources

Average Transverse Momenta in Hyperon Production at p-p Collider Experiments

The previously publicated analysis of transverse momentum spectra of $Λ^0$ hyperons from LHC experiments (ALICE, ATLAS, CMS)in the comparison with earlier experiments was reconsidered with correct spectra from STAR collaboration. The LHC data at $\sqrt{s}$ = 0.9 and 7 TeV and the data of proton-proton experiments of lower energies were fitted with the universal formula that includes the energy dependent slope as the main parameter. The dependence of average transverse momenta on $\sqrt{s}$ has been obtained with the help of this formula. The asymptotics of the energy dependence of average Pt shows the behavior $ ~ s^{0.05}$, that was not expected in early description of hadron transverse momentum in the framework of Quark-Gluon String Model. The previous important conclusion about spectra of cosmic rays was not changed: the long debated "knee" in the cosmic proton spectra at $E_p= (2,5 - 4)*10^{15}$ eV in laboratory system can not be considered any more as the result of dramatic changes in the dynamics of baryon hadroproduction. The reason of the steadily growing of average Pt seems situated outside the predictive power of QGSM. Nevertheless the average transverse momentum can reach a constant value with higher energies that has been predicted in our model long ago.

hep-ph

Leading Effects in the Spectra of $Λ_c$ and $\barΛ_c$ Produced in $Σ^-p$, $pp$ and $π^-p$ Interactions

The spectra of leading and nonleading charmed baryons ($Λ_c$ and $\barΛ_c$) as well as the asymmetries between these spectra measured in $Σ^-A$, $π^-A$ and pA collisions at $p_L= 600 GeV/c$ in the E781 experiment are simultaneously described within the framework of Quark-Gluon String Model (QGSM). It is shown that the charmed baryon spectra can be fitted by QGSM curves calculated with the parameter of diquark fragmentation, $a_f^{Λ_c}$=0.006. It was obtained in this experiment that the asymmetry between the spectra of $Λ_c$ and $\barΛ_c$ in $π^-A$ collisions is of nonzero value. It might be described in our model only assuming that the string junction is transfered from target proton into the kinematical region of pion projectile fragmentation.

hep-ph

Leading/nonleading charm production asymmetry in $Σ^-p$ interactions

The asymmetries between the spectra of leading and nonleading charmed mesons measured in $Σ^-A$ interactions at $p_L$= 340 GeV/c in the WA89 experiment are described in the framework of Quark-Gluon String Model. There are two versions of the model under consideration: one of them includes the sea charm quark-antiquark pairs and the other one does not. It's shown that the asymmetries between $D^-$ and $D^+$-meson spectra and between $D_s^-$ and $D^+_s$- meson spectra can be fitted by QGSM curves obtained with the same parameters as charm asymmetry in $π^-A$ experiments described in previous studies. The QGSM results are compared with the calculations in the next-to-leading approximation of perturbative QCD approach carried out by the other authors.

hep-ph