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E. S. Kokoulina

Publications and source records attributed to E. S. Kokoulina.

18 recordsLinked to original sources
arXiv2026

Gluon dominance model and multiparticle production

The gluon dominance model describes multiparticle production of secondary particles at high energies in lepton and hadron interactions, including annihilation processes and heavy quarkonium decays. According to this model, the multiparticle process is divided into two stages. The first stage describes the development of a quark-gluon cascade as a Markov branching process in the region of perturbation QCD. For the second stage, the transformation of quarks and gluons into observable hadrons (hadronization), a phenomenological scheme is proposed. It is universal and based on an experiment. The gluon dominance model demonstrates good agreement with data over a wide energy region. It testifies that in hadron interactions valence quarks remain in the leading particles, and gluons are the sources of secondary hadrons. Quantitative estimates of the model parameters confirm the fragmentation mechanism of hadronization in leptonic interactions and the recombination mechanism in hadronic ones. The model description of the experimental distributions on the number of neutral pions in proton interactions at 50 GeV beams in the high multiplicity region are presented for the first time. It is shown that the main contribution to this region is made by gluon fission. These results can be useful in planning of future experiments.

hep-ex↗
arXiv2026

Multiparticle production in electron-positron annihilation

Multiparticle production in hadron and lepton interactions still attracts our attention. Simulation by using Monte Carlo event generators is performed before planning any experiment. But it often overestimates (or underestimates) experimental data. These generators are based on the theory of strong interactions, quantum chromodynamics (QCD), which is capable of performing calculations only in the perturbation theory. Soft processes that make up a significant contribution in high-energy interactions are forced to involve phenomenological models. Of all multiparticle production processes, electron-positron annihilation is the theoretically cleanest, proceeding via an intermediate virtual photon or $Z^0$-boson followed by quark-antiquark pair creation. QCD describes well the development of quark-gluon ($qg$) cascade as marcovian branching process, that is called first stage. The transformation of quarks and gluons produced in the $qg$-cascade into observable hadrons occurs in the second stage, hadronization, to which perturbation theory is no longer applicable. The choice of a scheme for it is based on experimental data. Convolution of $qg$-cascade and hadronization allowed us to describe the multiplicity in practice all processes of multiple production in both lepton and hadron high-energy collisions. This model is called the gluon dominance model. Several decades have passed since a series of $e^+e^-$ annihilation experiments were carried out. Now, the main interests of high energy physicists are focused on the study of multiparticle production in proton and heavy ion collisions. Their research revealed many new results in the theory of strong interactions, including the hadronization. That is why it appeared necessary to analyze multiplicity n $e^+e^-$-annihilation again.

hep-ph↗
arXiv2015

Multiplicity description by gluon model

Study of high multiplicity events in proton-proton interactions is carried out at the U-70 accelerator (IHEP, Protvino). These events are extremely rare. Usually, Monte Carlo codes underestimate topological cross sections in this region. The gluon dominance model (GDM) was offered to describe them. It is based on QCD and a phenomenological scheme of a hadronization stage. This model indicates a recombination mechanism of hadronization and a gluon fission. Future program of the SVD Collaboration is aimed at studying a long-standing puzzle of excess soft photon yield and its connection with high multiplicity at the U-70 and Nuclotron facility at JINR, Dubna.

hep-ph↗
arXiv2015

Light meson emission in (anti)proton induced reactions

Reactions induced by high energy antiprotons on proton on nuclei are accompanied with large probability by the emission of a few mesons. Interesting phenomena can be observed and QCD tests can be performed, through the detection of one or more mesons. The collinear emission from high energy (anti)proton beams of a hard pion or vector meson, can be calculated similarly to the emission of a hard photon from an electron \cite{Kuraev:2013izz}. This is a well known process in QED, and it is called the "Quasi-Real Electron method", where the incident particle is an electron and a hard photon is emitted leaving an 'almost on shell' electron impinging on the target \cite{Baier:1973ms}. Such process is well known as Initial State Emission (ISR) method of scanning over incident energy, and can be used, in the hadron case, to produce different kind of particles in similar kinematical conditions. In case of emission of a charged light meson, $π$ or $ρ$-meson, in proton-proton(anti-proton) collisions, the meson can be deviated in a magnetic field and detected. The collinear emission (along the beam direction) of a charged meson may be used to produce high energy (anti)neutron beams. This can be very useful to measure the difference of the cross sections of (anti)proton and (anti)neutron scattering from the target and may open the way for checking sum rules with antiparticles. Hard meson emission allows also to enhance the cross section when the energy loss from one of the incident particles lowers the total energy up to the mass of a resonance. The cross section can be calculated, on the basis of factorized formulas, where the probability of emission of the light mesons multiplies the cross section of the sub-process. Multiplicity distributions for neutral and charged meson production are also given.

hep-ph↗
arXiv2013

Hard light meson production in (anti)proton-hadron collisions and charge-echange reactions

An extension of the QED 'return to resonance' mechanism to light meson emission ($π$, $ρ$) in (anti)proton collisions with a hadronic target (nucleon or nucleus) is proposed. The cross section and the multiplicity distributions are calculated. The collinear emission (along the beam direction) of a charged meson may be used to produce high energy (anti)neutron beams. Possible applications at existing and planned facilities are considered.

hep-ph↗
arXiv2012

A new conception in describing the Drell-Yan type processes

A set of evolution equations for correlators of densities of quark and gluons is considered. Approximate solutions is obtained in frames of gluon and quark dominance. A new formulation of the cross sections of Drell-Yan process is suggested. Differential cross sections for the QCD sub-processes of type $2 \to 2$ are obtained. Sub-process $g b\to tH^-$ as well considered.

hep-ph↗
arXiv2011

Neutral pion number fluctuations at high multiplicity in pp-interactions at 50 GeV

Neutral pion number N0 distributions for each total number of particles in event Ntot=Nch+N0 are obtained. The scaled variance of neutral pion fluctuations, omega=D/ , is measured. The fluctuations increase at Ntot >22. According to quantum statistics models it may indicate for the approaching to pion condensate conditions for high pion multiplicity in the system.

hep-ex↗
arXiv2011

Proton interactions with high multiplicity

Project Thermalization (Experiment SERP-E-190 at IHEP) is aimed to study the proton - proton interactions at 50 GeV with large number of secondary particles. In this report the experimentally measured topological cross sections are presented taking into account the detector response and procession efficiency. These data are in good agreement with gluon dominance model. The comparison with other models is also made and shows no essential discrepancies.

hep-ex↗
arXiv2011

Azimuthal correlation of gluon jets created in proton-antiproton annihilation

Annihilation process of proton and antiproton to guark antiquark pair accompanied by emission of two additional gluon jets with intermediate state of vector meson is considered.Strong azimuthal correlation is revealed of two gluonic jets,effectively created in the same plane.Some applications to cosmic ray events and to LHC experiments are discussed.

hep-ph↗
arXiv2007

Multiparticle Production at High Multiplicities

Theoretical and experimental studies of high multiplicity events are analyzed. Some interesting phenomena can be revealed at high multiplicities. Preliminary results of project "Thermalization" are reported.

hep-ph↗
arXiv2005

Gluon Dominance Model

A new way to study the multiplicity production in high energy processes is proposed. It is based on the multiplicity distribution description by the schemes taking into account the formation of quark-gluon system and hadronization. This investigations revealed an active role of gluons and the universal mechanism of their hadronization.

hep-ph↗
arXiv2005

Study of multiparticle production by gluon dominance model (Part II)

The gluon dominance model presents a description of multiparticle production in proton-proton collisions and proton-antiproton annihilation. The collective behavior of secondary particles in $pp$-interactions at 70 GeV/c and higher is studied in the project {\bf "Thermalization"}. The obtained neutral and charged multiplicity distribution parameters explain some RHIC-data. The gluon dominance model is modified by the inclusion of intermediate quark topology for the multiplicity distribution description in the pure $p\bar p$-annihilation at few tens GeV/c and explains behavior of the second correlative moment. This article proposes a mechanism of the soft photon production as a sign of hadronization. Excess of soft photons allows one to estimate the emission region size.

hep-ph↗
arXiv2005

Study of multiparticle production by Gluon Dominance Model

The gluon dominance model offers a description of multiparticle production in e^+e- - annihilation and proton-proton collisions. The multiplicity distributions in e^+e^- annihilation are well described. The energy dependence of model parameters gives the dynamic parton stage and hadronisation picture. It is shown that this model has confirmed oscillations in sign of the ratio of factorial cumulant moments over factorial moments of the increasing order. The collective behavior of secondary particles in $pp$-interactions at 70 GeV/c is studied in the project "Thermalization". An active role of gluons is shown in the multiparticle dynamics. This paper gives a simple thermodynamic interpretation of interactions mentioned above.

hep-ph↗
arXiv2004

Excitation of Physical Vacuum

Introducing such a notion as a "excitation of physical vacuum" we do an attempt to explain some strange experimental facts such as large value of $σ$-term measured in pion-nucleon low energy scattering, $ΔT=1/2$ rule in kaon two pion decay modes, the ratio of strange to nonstrange yield in low energy proton-antiproton annihilation, excess of soft photons in hadron's collisions. As a test of our approach we suggest to measure the multiparticle production processes and decays of heavy virtual objects.

hep-ph↗
arXiv2002

Multiplicity Distribution studies of $e^+e^-$-annihilation at 50-61.4 GeV and 172-189 GeV by Two Stage Model hadronization

The multiplicity distributions at high energy $e^+e^-$ annihilation are described well within the Two Stage Model in the region from 14 to 189 GeV. Energy dependence of parameters of this model gives the dynamic picture of the parton stage and the stage of hadronization. It is shown that oscillations in sign of the ratio of factorial cumulant moments over factorial moments of increasing order can be confirmed by this model.

hep-ph↗