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A. A. Rostovtsev

Publications and source records attributed to A. A. Rostovtsev.

12 recordsLinked to original sources

Two components in charged particle production in heavy-ion collisions

Transverse momentum spectra of charged particle production in heavy-ion collisions are considered in terms of a recently introduced Two Component parameterization combining exponential ("soft") and power-law ("hard") functional forms. The charged hadron densities calculated separately for them are plotted versus number of participating nucleons, $N_{part}$. The obtained dependences are discussed and the possible link between the two component parameterization introduced by the authors and the two component model historically used for the case of heavy-ion collisions is established. Next, the variations of the parameters of the introduced approach with the center of mass energy and centrality are studied using the available data from RHIC and LHC experiments. The spectra shapes are found to show universal dependences on $N_{part}$ for all investigated collision energies.

hep-ph↗

Role of quarks in hadroproduction in high energy collisions

Qualitative model for hadroproduction in high energy collisions considering two components ("thermal" and "hard") to hadroproduction is proposed. Inclusive pseudorapidity distributions, $dσ/dη$, and transverse momentum spectra, $d^2σ/(dηdp_T^2)$, measured by different collaborations are considered in terms of this model. The shapes of the pseudorapidity distributions agree with that one can expect from the qualitative picture introduced. Finally, the differences between charged particle spectra produced in inclusive and diffractive events are discussed and the absence of the "thermal" component in the latter is observed.

hep-ph↗

Hydrodynamic extension of the two component model for hadroproduction in heavy-ion collisions

The dependence of the spectra shape of produced charged hadrons on the size of a colliding system is discussed using a two component model. As a result, the hierarchy by the system-size in the spectra shape is observed. Next, the hydrodynamic extension of the two component model for hadroproduction using recent theoretical calculations is suggested to describe the spectra of charged particles produced in heavy-ion collisions in the full range of transverse momenta, $p_T$. Data from heavy-ion collisions measured at RHIC and LHC are analyzed using the introduced approach and are combined in terms of energy density. The observed regularities might be explained by the formation of QGP during the collision.

hep-ph↗

A photon-proton marriage

The shapes of invariant differential cross section for charged hadron production as function of hadron's transverse momentum and rapidity in ep collisions at HERA machine are considered. The particle spectra shapes observed in pp and gamma-gamma collisions before have shown very different properties. This difference could be directly measured in the "mixed" type collisions of photon and proton at HERA experiments.

hep-ph↗

Hadroproduction in heavy-ion collisions

The shapes of invariant differential cross section for charged particle production as function of transverse momentum measured in heavy-ion collisions are analyzed. The data measured at RHIC and LHC are treated as function of energy density according to a recent theoretical approach. The Boltzmann-like statistical distribution is extracted from the whole statistical ensemble of produced hadrons using the introduced model. Variation of the temperature, characterizing this exponential distribution, is studied as function of energy density.

hep-ph↗

A variation of the charged particle spectrum shape as function of rapidity in high energy pp collisions

The shapes of invariant differential cross section for charged particle production as function of transverse momentum measured in pp collisions by the UA1 detector are analyzed. The spectra shape varies with the produced particle's pseudorapidity changing. To describe this and several other recently observed effects a simple qualitative model for hadroproduction mechanism was proposed.

hep-ph↗

An analysis of charged particles spectra in events with different charged multiplicity

The shapes of invariant differential cross section for charged particle production as function of transverse momentum measured in $pp$ collisions by the STAR detector are analyzed. The spectra shape varies with the event charged multiplicity changing. To describe this and several other recently observed effects a simple qualitative model for hadroproduction mechanism was proposed.

nucl-th↗

Comparative Analysis of Pion, Kaon and Proton Spectra Produced at PHENIX

The shapes of invariant differential cross section for identified pi,K, p and pbar production as function of transverse momentum measured in pp collisions by the PHENIX detector are analyzed. Simultaneous fit of these data to the sum of exponential and power-law terms show significant difference in the exponential term contributions. This effect qualitatively explains the observed shape of the experimental K/pi and p/pi yield ratios measured as function of transverse momentum of produced hadrons. A picture with two types of mechanisms for hadron production is given.

hep-ph↗

Anomalous behavior of pion production in high energy particle collisions

A shape of invariant differential cross section for charged hadron production as function of transverse momentum measured in various collider experiments is analyzed. Contrary to the behavior of produced charged kaons, protons and antiprotons, the pion spectra require an anomalously high contribution of an exponential term to describe the shape.

hep-ph↗

Systematic studies of hadron production spectra in collider experiments

A shape of invariant differential cross section for hadron production as function of transverse momentum is analysed. The systematic analysis of the available data demonstrates a need for a modification of the parameterization traditionally used to approximate the measured spectra. The properties of the new proposed parameterization are discussed.

hep-ph↗

Permafrost - An Alternative Target Material for Ultra High Energy Neutrino Detection?

The detection of cosmic neutrinos with energies above 1017 eV got growing interest during recent years. Possible target materials for in-matter arrays of ~100 km3 size under discussion are water, ice and rock salt. Here we propose to investigate permafrost as an additional alternative, covering ~20% of Earth land surface and reaching down to more than 1000 m depth at certain locations. If sufficiently large attenuation lengths for radio and acoustic signals can be demonstrated by in-situ measurements, the construction of a large hybrid array within this material may be possible in the Northern hemisphere. Properties and problems of a possible location in Siberia are discussed below. Some acoustic data are compared to laboratory measurements using "artificial" permafrost.

astro-ph↗

Evidence for unusual events in high energy cosmic ray interactions

Anomalous events with a large transverse momenta $P_T$ were found for all secondary particles in an analysis of experimental data on cosmic ray interactions at $E_0 > 5\cdot 10^{13} eV$. In order to clarify the underlying mechanism of these events, the intermittency analysis of interactions with both large and usual transverse momentum was performed. It is shown that behavior of intermittency indices $ϕ(q)$ as a function of rank factorial momentum $q$ for such interactions is very peculiar. The indices show slight growth for the events with large transverse momenta for all secondary particles in contrast with the fast growth for events with normal average transverse momenta for final particles. The significant difference in the behavior of intermittency indices gives strong evidence on the existence of the new class of hadron interactions with large $P_T$ for all secondary particles in the event. A possible interpretation of these anomalous events as a manifistation of Color Glass Condensate in high energy hadron-hadron interactions is given.

astro-ph↗