arXiv subjects

V. Emel'yanov

Publications and source records attributed to V. Emel'yanov.

8 recordsLinked to original sources

arXiv1999

The Effect of Shadowing on Initial Conditions, Transverse Energy and Hard Probes in Ultrarelativistic Heavy Ion Collisions

The effect of shadowing on the early state of ultrarelativistic heavy ion collisions is investigated along with transverse energy and hard process production, specifically Drell-Yan, $J/ψ$, and $Υ$ production. We choose several parton distributions and parameterizations of nuclear shadowing, as well as the spatial dependence of shadowing, to study the influence of shadowing on relevant observables. Results are presented for Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and Pb+Pb collisions at $\sqrt{s_{NN}} = 5.5$ TeV.

hep-ph↗

arXiv1999

Shadowing Effects on Particle and Transverse Energy Production

The effect of shadowing on the early state of ultrarelativistic heavy ion collisions and transverse energy production is discussed. Results are presented for RHIC Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and LHC Pb+Pb collisions at $\sqrt{s_{NN}} = 5.5$ TeV.

hep-ph↗

arXiv1998

Impact Parameter Dependence of $J/ψ$ and Drell-Yan Production in Heavy Ion Collisions at $\sqrt{s_{NN}} = 17.3$ GeV

In heavy-ion collisions, $J/ψ$ and Drell-Yan production are expected to be affected by nuclear modifications to the free nucleon structure functions. If these modifications, known as shadowing, are proportional to the local nuclear density, the per nucleon cross sections will depend on centrality. Differences in quark and gluon shadowing will lead to a new source of impact parameter dependence of the $J/ψ$ to Drell-Yan production ratio. We calculate this ratio in the CERN NA50 acceptance with several shadowing parameterizations to explore its centrality dependence.

hep-ph↗

arXiv1998

Spatial Variation of Nuclear Structure Functions and Heavy Quark Production

We explore how nuclear modifications to the free nucleon structure functions (also known as shadowing) affect heavy quark production in collisions at different impact parameters. We assume that the nuclear modifications arise from a density dependent effect such as gluon recombination and are thus proportional to the local density. We calculate the dependence of charm and bottom quark production on impact parameter and show that density dependent modifications can lead to significant reductions in the heavy quark production cross sections in central relative to peripheral interactions.

nucl-th↗

arXiv1997

Charm Quark Production in Non-central Heavy Ion Collisions

The effect of gluon shadowing on charm quark production in large impact parameter ultrarelativistic heavy ion collisions is investigated. Charm production cross sections are calculated for a range of non-central impact parameters which can be accurately inferred from the global transverse energy distribution. We show that charm production is a good probe of the local parton density which determines the effectiveness of shadowing. The spatial dependence of shadowing can only be studied in heavy ion collisions.

nucl-th↗

arXiv1994

On the $M_T$ scaling of dilepton spectra in high energy heavy ion collisions

The so-called $M_T$ scaling for dilepton spectra at RHIC energies is examined. It is seen that a proper accounting of the complete set of dilepton producing processes forces us to abandon the proposed scaling around $M_T$ = 2.6 GeV, which has been put forward as a possible signature of the presence of quark-matter. Any substantial transverse expansion in the QGP phase itself will also offset this scaling behaviour. The rates of lepton pair production are time--integrated in Bjorken hydrodynamics and the different sources are compared against each other.

nucl-th↗

arXiv1992

Soft dilepton production in relativistic heavy ion collisions

Production of electron-positron pairs with invariant masses less than 300 MeV from thermalized hadronic matter in relativistic heavy ion collisions is calculated using a soft virtual photon approximation. The general theoretical framework is reviewed and extended to include arbitrarily massed and charged reaction partners, which we apply to pions and quarks. This result, exact within the soft photon approximation, is compared with a widely used approximate result which uses an electromagnetic amplitude limited in validity to momentum transfers less than $4m_{π(q)}^{2}$. A comparison is made between the rate of production of zero total momentum soft dileptons obtained using resummation techniques in QCD perturbation theory to that which we calculate using this soft photon approximation.

hep-ph↗

arXiv1992

Virtual bremsstrahlung from pions and quarks in thermalized hadronic matter

A soft photon approximation is used to calculate the rates of lepton pair production through virtual bremsstrahlung from both pions and quarks. Standard assumptions about the evolution of a nuclear system under collision allow pion and quark driven total production to be calculated. Comparisons are made with Dalitz decay of light mesons. These mechanisms are expected to be significant contributors to the soft dilepton mass spectra one might observe in heavy ion collisions at RHIC and LHC energies.

hep-ph↗