Searcharxiv⌕ Search

arXiv subjects

I. P. Lokhtin

Publications and source records attributed to I. P. Lokhtin.

At least 55 records · Page 3Linked to original sources
arXiv2005

A model of jet quenching in ultrarelativistic heavy ion collisions and high-pt hadron spectra at RHIC

The method to simulate the rescattering and energy loss of hard partons in ultrarelativistic heavy ion collisions has been developed. The model is a fast Monte-Carlo tool introduced to modify a standard PYTHIA jet event. The full heavy ion event is obtained as a superposition of a soft hydro-type state and hard multi-jets. The model is applied to analysis of the jet quenching pattern at RHIC.

hep-ph↗
arXiv2005

Jet activity versus alignment

The hypothesis about the relation between the observed alignment of spots in the x-ray film in cosmic ray emulsion experiments and the features of events in which jets prevail at super high energies is tested. Due to strong dynamical correlation between jet axis directions and that between momenta of jet particles (almost collinearity), the evaluated degree of alignment is considerably larger than that for randomly selected chaoticly located spots in the x-ray film. It appears comparable with experimental data provided that the height of primary interaction, the collision energy and the total energy of selected clusters meet certain conditions. The Monte Carlo generator PYTHIA, which basically well describes jet events in hadron-hadron interactions, was used for the analysis.

hep-ph↗
arXiv2004

Pt-imbalance in dimuon+jet production as a signal of partonic energy loss in heavy ion collisions at LHC

We consider a hard jet production tagged by a muon pair in ultrarelativistic heavy ion collisions. The process cross section is calculated by the CompHEP Monte-Carlo generator taking into account full gamma*/Z interference pattern at LHC energies. We have found that reasonable statistics, ~1000 events per 1 month of LHC run with lead beams, can be expected for realistic geometrical acceptance and kinematic cuts. The transverse momentum imbalance due to interactions of jet partons in the medium is evaluated for mu+mu-pair+jet correlation, as well as for the correlation between mu+mu- pair and a leading particle in a jet. Theoretical and experimental uncertainties of these observables are discussed.

hep-ph↗
arXiv2004

Medium-modified fragmentation of b-jets tagged by a leading muon in ultrarelativistic heavy ion collisions

The possibility to observe the medium-modified fragmentation of hard b-quarks tagged by a leading muon in ultrarelativistic heavy ion collisions is analyzed. We have found that reasonable statistics, ~20000 events per 1 month of LHC run with lead beams, can be expected for the realistic geometrical acceptance and kinematic cuts. The numerical estimates on the effect of the medium-induced softening b-jet fragmentation function are given.

hep-ph↗
arXiv2004

Photon Physics in Heavy Ion Collisions at the LHC

Various pion and photon production mechanisms in high-energy nuclear collisions at RHIC and LHC are discussed. Comparison with RHIC data is done whenever possible. The prospect of using electromagnetic probes to characterize quark-gluon plasma formation is assessed.

hep-ph↗
arXiv2004

Calorimetric transverse energy-energy correlations as a probe of jet quenching

The sensitivity of calorimetric energy-energy correlation function to the medium-induced energy loss of fast partons in high multiplicity heavy ion interactions is demonstrated at the appropriate selection of events for the analysis, namely, the availability of one high-pt jet in an event at least and using the procedure of ``thermal'' background subtraction. Without jet trigger this correlation function manifests the global structure of transverse energy flux: the correlator is isotropic for central collisions, and for non-central collisions it is sensitive to the azimuthal anisotropy of energy flow reproducing its Fourier harmonics but with the coefficients squared.

hep-ph↗
arXiv2003

Hard probes in heavy ion collisions at the LHC: heavy flavour physics

We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for $pp$ and $pA$ collisions at the LHC against which the $AA$ rates can be compared in the study of the quark-gluon plasma. We also provide an assessment of the theoretical uncertainties in these benchmarks. We then discuss some of the cold matter effects on quarkonia production, including nuclear absorption, scattering by produced hadrons, and energy loss in the medium. Hot matter effects that could reduce the observed quarkonium rates such as color screening and thermal activation are then discussed. Possible quarkonium enhancement through coalescence of uncorrelated heavy quarks and antiquarks is also described. Finally, we discuss the capabilities of the LHC detectors to measure heavy quarks and quarkonia as well as the Monte Carlo generators used in the data analysis.

hep-ph↗
arXiv2003

Partonic energy loss in ultrarelativistic heavy ion collisions: jet suppression versus jet fragmentation softening

We discuss the modification of a jet fragmentation function due to medium-induced partonic energy loss in context of leading particle observables in ultrarelativistic nucleus-nucleus interactions. We also analyze the relation between in-medium softening jet fragmentation function and suppression of the jet rates due to energy loss outside the jet cone. The predicted anti-correlation between two effects allows to probe a fraction of partonic energy loss carried out of the jet cone and truly lost to the jet.

hep-ph↗
arXiv2003

Extracting the jet azimuthal anisotropy from higher order cumulants

We analyze the method for calculation of a coefficient of jet azimuthal anisotropy without reconstruction of the nuclear reaction plane considering the higher order correlators between the azimuthal position of jet axis and the angles of particles not incorporated in the jet. The reliability of this technique in the real physical situation under LHC conditions is illustrated.

hep-ph↗
arXiv2002

Jet quenching and high-pt azimuthal asymmetry

The azimuthal anisotropy of high-pt particle production in non-central heavy ion collisions is among the most promising observables of partonic energy loss in an azimuthally non-symmetric volume of quark-gluon plasma. We discuss the implications of nuclear geometry for the models of partonic energy loss in the context of recent RHIC data and consequences for observation of jet quenching at the LHC.

hep-ph↗
arXiv2002

Photon-jet correlation in heavy ion collisions at the LHC

Transverse momentum imbalance between a jet produced with a hard photon is considered as a signal of medium-induced partonic energy loss in ultrarelativistic heavy ion collisions. We analyze photon-jet correlation in the context of a real experimental situation at the LHC, the problem of neutral pion background being discussed.

hep-ph↗
arXiv2002

Rapidity distribution of jet quenching: effects on global observables

We discuss modification in the rapidity distribution of the transverse energy flow as a signal of medium-induced partonic energy loss in ultrarelativistic heavy ion collisions. A scan of the global energy flow and jet rates in the wide rapidity region might provide the important information about the pseudo-rapidity size of a dense medium created in heavy ion collisions at the LHC.

hep-ph↗
arXiv2002

Jet and Dijet Rates in AB Collisions

Jet and dijet rates in AB collisions at LHC energies are computed using a NLO Monte Carlo code. Uncertainties due to nuclear modifications of nucleon parton densities are analyzed. Predictions for different AB collisions at LHC energies are presented.

hep-ph↗
arXiv2002

Jet quenching in heavy ion collisions at LHC

We discuss the potential information about highly excited QCD-matter provided by medium-induced partonic energy loss, known as ``jet quenching''. In particular, with its large acceptance hadronic and electromagnetic calorimetry, the Compact Muon Solenoid detector at LHC collider is a promising device to study these effects. We present physics simulations of observables such as the jet distribution with impact parameter, the azimuthal anisotropy of jet quenching, and the effects of b-quark energy loss on the high-mass dimuon continuum and secondary charmonium production.

hep-ph↗
arXiv2002

A method for analysing the jet azimuthal anisotropy in ultrarelativistic heavy ion collisions

The azimuthal anisotropy of jet spectra due to energy loss of jet partons in azimuthally non-symmetric volume of dense quark-gluon matter is considered for semi-central nuclear interactions at collider energies. We develop the techniques for event-by-event analysing the jet azimuthal anisotropy using particle and energy elliptic flow, and suggest a method for calculation of coefficient of jet azimuthal anisotropy without reconstruction of nuclear reaction plane.

hep-ph↗