arXiv subjects

M. V. Tokarev

Publications and source records attributed to M. V. Tokarev.

At least 19 recordsLinked to original sources

arXiv2021

First indication on self-similarity of strangeness production in $Au+Au$ collisions at RHIC: Search for signature of phase transition in nuclear matter

New results of analysis of $K^0_S-$meson spectra measured over a wide range of energy $\sqrt {s_{NN}}=7.7-200$ GeV and centrality in $Au+Au$ collisions by the STAR Collaboration at RHIC using the $z$-scaling approach are presented. Indication on self-similarity of fractal structure of nuclei and fragmentation processes with $K^0_S$ probe is demonstrated. The energy loss as a function of the collision energy, centrality and transverse momentum of the inclusive strange meson is estimated.

hep-ph↗

arXiv2015

Self-similarity of negative particle production from the Beam Energy Scan Program at STAR

We present the spectra of negative charged particle production in Au+Au collisions from STAR for the first phase of the RHIC Beam Energy Scan Program measured over a wide range of collision energy sqrt s{NN}=7.7-200 GeV, and transverse momentum of produced particle in different centralities at |eta|<0.5. The spectra demonstrate strong dependence on collision energy which enhances with pT. An indication of self-similarity of negative charged particle production in Au+Au collisions is found. The constituent energy loss as a function of energy and centrality of collisions and transverse momentum of inclusive particle was estimated in the $z$-scaling approach. The energy dependence of the model parameters - the fractal and fragmentation dimensions and "specific heat", was studied.

nucl-ex↗

arXiv2011

Saturation of Hadron Production in Proton-(anti)Proton Collisions at Low Pt

Experimental data on inclusive cross sections of the hadrons produced in high energy proton-(anti)proton collisions are analyzed in the z-scaling approach. Saturation of the scaling function PSI(z) for z<0.1 (low transverse momenta) was found. The first results on charged hadron spectra in pp collisions obtained by the CMS Collaboration at the LHC have confirmed the saturation down to the value of z=0.05. The CMS data on neutral K-meson production at s^{1/2}=7 TeV extend the saturation region even to a lower value of z=0.002 in the new energy domain. A microscopic scenario of hadron production at a constituent level based on the z-scaling is discussed in the saturation regime.

hep-ph↗

arXiv2010

High-pT Spectra of Charged Hadrons in Au+Au Collisions at sqrt s_(NN)=9.2 GeV in STAR

The production of hadrons in heavy ions collisions at high $p_T$ provides an important information on mechanism of particle formation and constituent energy loss in medium. Such information is needed for search of a Critical Point and signatures of phase transition. Measurements by the STAR Collaboration of charged hadron production in Au+Au collisions at $\sqrt {s_{NN}}$=9.2 GeV over a wide transverse momentum $p_T=0.2-4.$ GeV/c and at mid-rapidity range are reported. It allows for a first measurement of the spectra for charged hadrons at high $p_T$ at this energy. The spectra demonstrate the dependence on centrality which enhances with $p_T$. The constituent energy loss and its dependence on transverse momentum of particle, and centrality of collisions are estimated in the $z$-scaling approach.

nucl-ex↗

arXiv2010

On saturation of charged hadron production in pp collisions at LHC

First results on charged hadron transverse momentum spectra in pp collisions obtained by the CMS Collaboration at LHC were analyzed in z-scaling approach. The first LHC data confirm z-scaling. The saturation regime of the scaling function psi(z) observed in pp and antp-pp interactions at lower energy sqrt s = 19-1960 GeV is verified. The saturation of psi(z) for charged hadrons is found down to z=0.05 at the highest energy sqrt s = 2360 GeV reached till now at colliders. A microscopic scenario of hadron production is discussed in connection with search for new signatures of phase transitions in hadron matter. Constituent energy loss and its dependencies on the transverse momentum of charged hadrons and collision energy are estimated. The beam energy scan at LHC in the saturation region is suggested.

hep-ph↗

arXiv2008

New properties of z-scaling: flavor independence and saturation at low z

Experimental data on inclusive cross sections of particles produced in high energy proton-(anti)proton collisions at ISR, RHIC, and Tevatron are analyzed in the framework of $z$-scaling. New features of the scaling function $ψ(z)$ are established. These are flavor independence of $ψ(z)$ including particles with heavy flavor content and saturation at low $z$. The flavor independence means that the shape of the scaling function $ψ(z)$ is the same for different hadron species. The saturation corresponds to flattening of $ψ(z)$ for $z<0.1$. Relations of model parameters used in data $z$-presentation with some thermodynamical quantities (entropy, specific heat, temperature) are discussed. It is shown that behavior of the particle spectra at low $z$ is controlled by a parameter $c$ interpreted as a specific heat of the created medium associated with production of the inclusive particle. The saturation regime of $ψ(z)$ observed at low $z$ is assumed to be preferable in searching for phase transitions of hadron matter and for study of non-perturbative QCD in high energy proton-(anti)proton collisions at U70, RHIC, Tevatron, and LHC.

hep-ph↗

arXiv2007

Jets in pp collisions at RHIC and Monte Carlo study of z-scaling

Impact of the cone algorithm parameters Ecut, Eseed, R on the efficiency and characteristics of the reconstructed jets in p-p collisions at the energy sqrt s = 200 GeV is studied. The PYTHIA Monte Carlo generator is used for event generation. The dependence of dijet production fraction on the parton transverse momentum at different algorithm parameters is analyzed. The dependence of reconstruction efficiency of parton energy in dijet events and two leading jets in N-jet events on Ecut, Eseed, R is studied. Monte Carlo results are compared with predictions made in the framework of z-scaling and experimental data obtained at RHIC. The independence of the slope parameter beta of the scaling function, on the algorithm parameters over the energy range ETJet=25-60 GeV is found. The strong dependence of the invariant cross section and the slope parameter on the algorithm parameters with decreasing of ETJet for ETJet<25 GeV is observed.

hep-ph↗

arXiv2005

Z-Scaling and Inclusive Particle Production in p-p Collisions at High-pT

The properties of particle production in pp collisions are basis for analysis of pA and AA interactions and verification of theory. We analyzed inclusive particle production using z-scaling established in proton-proton and proton-antiproton collisions at the U70, ISR, Tevatron and RHIC. This scaling reflects symmetry of hadron structure, interaction and particle formation. It is shown that new data on charged hadron and pi0-meson spectra obtained in pp collisions at the Relativistic Heavy Ion Collider confirm the z-scaling.

hep-ph↗

arXiv2004

Z-Scaling of Jet Production at Tevatron

New data on jet production obtained by the CDF and D0 Collaborations at the Tevatron in Run II are analyzed in the framework of z-scaling. Properties of data z-presentation are discussed. Physics interpretation of the scaling function psi(z) as a probability density to produce a particle with the formation length z is argued. It was shown that these experimental data confirm z-scaling.

hep-ph↗

arXiv2004

Jet Energy Density in Hadron-Hadron Collisions at High Energies

The average particle multiplicity density dN/deta is the dynamical quantity which reflects some regularities of particle production in low-pT range. The quantity is an important ingredient of z-scaling. Experimental results on charged particle density are available for pp, pA and AA collisions while experimental properties of the jet density are still an open question. The goal of this work is to find the variable which will reflect the main features of the jet production in low transverse energy range and play the role of the scale factor for the scaling function psi(z) and variable z in data z-presentation. The appropriate candidate is the variable we called "scaled jet energy density". Scaled jet energy density is the probability to have a jet with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of scaled jet energy density in proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and at eta = 0. The properties of the new variable are discussed and sensitivity to "physical scenarios" applied in the standard Monte Carlo generator is noted. The results of scaled jet energy density at LHC energies are presented and compared with predictions based on z-scaling.

hep-ph↗

arXiv2004

Z-scaling at RHIC

The concept of z-scaling reflecting the general regularities of high-pT particle production is reviewed. Properties of data z-presentation are discussed. New data on high-pT particle spectra obtained at the RHIC are analyzed in the framework of z-presentation. It was shown that these experimental data confirm z-scaling. Predictions of strange particle spectra are considered to be useful for understanding of strangeness origin in mesons and baryons and search for new physics phenomena at the RHIC.

hep-ph↗

arXiv2004

z-Scaling and Prompt J/psi Production at High-pT in bar pp at Tevatron

New data on high-pT spectra of J/psi measured by the CDF Collaboration at the Tevatron are analyzed in the framework of z-scaling. F-dependence of z-presentation of the data is used to construct the scaling function of J/psi. The energy independence of the scaling function is used to predict inclusive cross section of prompt J/psi production in bar pp collisions at high-pT. The concept of z-scaling is considered to reflect the general features of high-pT particle production in hadron-hadron and hadron-nucleus collisions. Violation of z-scaling is suggested to consider as a signature of new physics.

hep-ph↗

arXiv2003

Z-scaling from tens of GeV to TeV

The concept of z-scaling reflecting the general features of internal particle substructure, constituent interaction and mechanism of particle formation at high-pT is reviewed. Experimental data on inclusive cross sections obtained at U70, ISR, SpS, RHIC and Tevatron are used in the analysis. The properties of data z-presentation such as the energy independence, power law and A-dependence are discussed. The properties of z-scaling are argued to be connected with the fundamental symmetries such as self-similarity, locality and fractality. The use of z-scaling to search for new physics phenomena in hadron-hadron and hadron-nucleus collisions is suggested. RHIC data used in our new analysis confirm z-scaling in pp collisions. High-pT particle spectra at LHC energies are predicted. Violation of z-scaling characterized by the change of anomalous fractal dimension is considered as a new and complementary signature of new physics phenomena.

hep-ph↗

arXiv2002

Scaling properties of hadron production in pi-p and pi-A collisions at high-pT

Scaling features of particles produced in pi-p and pi-A collisions over a high-pT range at high energies are studied. The general concept of z-scaling is applied for the analysis of pi-p and pi-A experimental data on the inclusive cross section. The scaling function psi(z) and scaling variable z are constructed and the anomalous dimension delta_pi is found. The A-dependence of particle production in pion-nucleus collisions is studied. The predictions of the inclusive cross section of the pi0-mesons produced in pi-A collisions in the central rapidity range at high energies have been made.

hep-ph↗

arXiv2001

Asymptotic properties of high-pT particle production in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions at high energies

The concept of z-scaling reflecting the general features of particle substructure, constituent interaction and mechanism of particle formation is reviewed. Experimental data on the cross sections obtained at ISR, SpS and Tevatron are used in the analysis. The properties of data z-presentation, the energy and angular independencies, the power law, A- and F-dependencies, are discussed. The use of z-scaling to search for new physics phenomena in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions is suggested. The violation of z-scaling characterized by the change of the fractal dimension is considered as a new and complimentary signature of nuclear phase transition.

hep-ph↗

arXiv2000

Asymmetry of p(->)+p(->)->gamma+jet+X process and problem of Delta G

The gamma +jet production in p(->)-p(->) collisions at high energies is studied. Double-spin asymmetry A{LL} of the process is calculated by using Monte Carlo code SPHINX. The predictions for A{LL} of the gamma +jet production in the p(->)-p(->) collisions using the spin-dependent gluon distributions with positive and negative sign of $ΔG(x,Q^2)$ are made at RHIC energies. A possibility to extract the spin-dependent gluon distributions Delta G at STAR experiment and to discriminate between different theoretical scenarios is discussed.

hep-ph↗

arXiv1999

Asymmetry of prompt photon production in p-p collisions at RHIC

The prompt photon production in p-p collisions at high energies is studied. Double-spin asymmetry of the process is calculated by using Monte Carlo code SPHINX. A possibility to discriminate the spin-dependent gluon distributions and to determine sign of Delta G is discussed. Detailed study of expected background, such as pi0 production and decay, is given. The predictions for the longitudinal asymmetry of the prompt photons and pi0-meson production in the p-p collisions at RHIC energies have been made.

hep-ph↗

arXiv1997

NNLO QCD Analysis of CCFR data on $xF_3$ Structure Function and Gross-Llewellyn Smith Sum Rule with Higher Twist and Nuclear Corrections

A detailed NNLO QCD analysis of new CCFR data on the $xF_3$ structure function including the target mass, higher twist and nuclear corrections was performed and parametrizations of the perturbative and power terms of the structure function were constructed. The results of QCD analysis of the structure function were used to study the $Q^2-$dependence of the Gross-Llewellyn Smith sum rule. The $α_S/π-$expansion of $S_{GLS}(Q^2)$ was studied and parameters of the expansion were found to be $s_1=2.74\pm 0.01$, $s_2=-2.22\pm 0.23$, $s_3=-7.86\pm 1.74$ in a good agreement with the perturbative QCD predictions for the Gross-Llewellyn Smith sum rule in the next-to-leading and next-to-next-to-leading order.

hep-ph↗