arXiv subjects

G. I. Lykasov

Publications and source records attributed to G. I. Lykasov.

At least 55 records · Page 3Linked to original sources

arXiv2011

Dynamical and thermal descriptions in parton distribution functions

We suggest a duality between the standard (dynamical) and statistical distributions of partons in the nucleons. The temperature parameter entering into the statistical form for the quark distributions is estimated. It is found that this effective temperature is practically the same for the dependence on longitudinal and transverse momenta and, in turn, it is close to the freeze-out temperature in high energy heavy-ion collisions.

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arXiv2011

Role of gluons in soft and semi-hard multiple hadron production in pp collisions at LHC

Hadron inclusive spectra in pp collisions are analyzed within the modified quark-gluon string model including both the longitudinal and transverse motion of quarks in the proton in the wide region of initial energies. The self-consistent analysis shows that the experimental data on the inclusive spectra of light hadrons like pions and kaons at ISR energies can be satisfactorily described at transverse momenta not larger than 1-2 GeV/c. We discuss some difficulties to apply this model at energies above the ISR and suggest to include the distribution of gluons in the proton unintegrated over the internal transverse momentum. It leads to an increase in the inclusive spectra of hadrons and allows us to extend the satisfactory description of the data in the central rapidity region at energies higher than ISR.

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arXiv2011

13th International Conference on Elastic and Diffractive Scattering (Blois Workshop) - Moving Forward into the LHC Era

Proceedings of the 13th International Conference on Elastic and Diffractive Scattering (Blois Workshop) - Moving Forward into the LHC Era

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arXiv2010

Forward production of heavy flavour hadrons in p-p collisions and intrinsic charm and bottom in proton

We present the theoretical results on the forward Lambda_b production in pp collisions obtained within the soft QCD, namely the quark gluon string model, at LHC energies. It can give us useful information on the Regge trajectories of the (b{\bar b}) mesons. An opportunity to find the information on the intrinsic charm and bottom in the proton by analyzing the forward heavy flavour hadron production in pp collisions is discussed.

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arXiv2010

Forward heavy baryon production in pp collisions at LHC

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arXiv2010

Gluons in proton and soft pp collisions at high energies

The hadron inclusive spectra in pp collisions at high energies are analyzed within a soft QCD model, namely the quark-gluon string model. In addition to the sea quark distribution in the incoming proton we consider also the unintegrated gluon distribution that has an increasing behaviour when the gluon transverse momentum grows. It leads to an increase of the inclusive spectra of hadrons and their multiplicity in the central rapidity region of pp collision at LHC energies.

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arXiv2010

Forward production of beauty baryons in pp collisions at LHC

The production of charmed and beauty baryons in proton-proton collisions at high energies is analyzed within the modified quark-gluon string model. We present some predictions for the experiments on the forward beauty baryon production in pp collisions at LHC energies. This analysis allows us to find useful information on the Regge trajectories of the heavy (b barb) mesons and the sea beauty quark distributions in the proton.

hep-ph↗

arXiv2010

Duality of thermal and dynamical descriptions in particle interactions

We suggest a duality between the statistical and standard (dynamical) distributions of partons in the nucleons. The temperature parameter entering into the statistical form for the quark distributions is estimated. It is found that this effective temperature is practically the same for the dependence on logitudinal and transverse momenta and, it is close to the freeze-out temperature in high energy heavy-ion collisions.

hep-ph↗

arXiv2010

Relativistic and spin effects in elastic backward p-d scattering

The elastic backward proton-deuteron scattering is analyzed including relativistic effects in the deuteron and the mechanism of this reaction which includes the graphs corresponding to the emission, rescattering and absorption of the virtual pion by a deuteron nucleon in addition to the one-nucleon exchange graph. It allows one to obtain a rather satisfactory description of all the experimental data on the differential cross section, tensor analyzing power of the deuteron and transfer polarization in this reaction.

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arXiv2009

Beauty baryon production in pp collisions at LHC and b quark distribution in proton

The production of charmed and beauty hadrons in proton-proton collisions at high energies are analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. We present some predictions for the future experiments on the beauty baryon production in $pp$ collisions at LHC energies. This analysis allows us to find interesting information on the Regge trajectories of the heavy (b{\bar b}) mesons and the sea beauty quark distributions in the proton.

hep-ph↗

arXiv2009

Thermal Effects for Quark and Gluon Distributions in Heavy-Ion Collisions

In-medium effects for distributions of quarks and gluons in central A+A collisions are considered. We suggest a duality principle, which means similarity of thermal spectra of hadrons produced in heavy-ion collisions and inclusive spectra which can be obtained within the dynamic quantum scattering theory. Within the suggested approach we show that the mean square of the transverse momentum for these partons grows and then saturates when the initial energy increases. It leads to the energy dependence of hadron transverse mass spectra which is similar to that observed in heavy ion collisions.

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arXiv2009

Transverse momentum spectra of D and B mesons in hadron collisions at high energies

Transverse momentum spectra of charmed and beauty mesons produced in proton-proton and proton-antiproton collisions at high energies are analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. It is shown that this approach can describe rather satisfactorily the experimental data at not large values of the transverse momentum where the NLO QCD calculation has a big uncertainty. We also show that using both the QGSM and the NLO QCD one can describe these data in a wide region of transverse momenta and give some predictions for the future LHC experiments.

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arXiv2008

Unified approach to structure factors and neutrino processes in nucleon matter

We present a unified approach to neutrino processes in nucleon matter based on Landau's theory of Fermi liquids that includes one- and two-quasiparticle-quasihole pair states as well as mean-field effects. We show how rates of neutrino processes involving two nucleons may be calculated in terms of the collision integral in the Landau transport equation for quasiparticles. Using a relaxation time approximation, we solve the transport equation for density and spin-density fluctuations and derive a general form for the response functions. We apply our approach to neutral-current processes in neutron matter, where the spin response function is crucial for calculations of neutrino elastic and inelastic scattering, neutrino-pair bremsstrahlung and absorption from strongly-interacting nucleons. We calculate the relaxation rates using modern nuclear interactions and including many-body contributions, and find that rates of neutrino processes are reduced compared with estimates based on the one-pion exchange interaction, which is used in current simulations of core-collapse supernovae.

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arXiv2008

Transverse momentum spectra of hadrons produced in central heavy-ion collisions

In-medium effects of transverse-mass distributions of quarks and gluons are considered assuming a possible local equilibrium for colorless quark objects like mesons and baryons created in central A+A collisions. It is shown that the average square of the transverse momentum for these partons grows and then saturates when the initial energy increases. Within the quark-gluon string model it leads to the energy dependence of hadron transverse mass spectra which is similar to that observed in heavy ion collisions. Comparison with other scenarios is given.

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arXiv2008

Collective effects in central heavy-ion collisions

In-medium effects on transverse-mass distributions of quarks and gluons are considered assuming a possible local equilibrium for colorless quark objects (mesons and baryons) created in central A-A collisions. It is shown that the average transverse momentum squared for these partons grows and then saturates when the initial energy increases. Within the quark-gluon string model it leads to the colliding energy dependence of hadron transverse mass spectra which is similar to that observed in heavy ion collisions. Comparison with other scenarios is given.

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arXiv2005

Long-wavelength spin- and spin-isospin correlations in nucleon matter

We analyse the long-wavelength response of a normal Fermi liquid using Landau theory. We consider contributions from intermediate states containing one additional quasiparticle-quasihole pair as well as those from states containing two or more additional quasiparticle-quasihole pairs. For the response of an operator corresponding to a conserved quantity, we show that the behavior of matrix elements to states with more than one additional quasiparticle-quasihole pair at low excitation energies $ω$ varies as $1/ω$. It is shown how rates of processes involving transitions to two quasiparticle-quasihole states may be calculated in terms of the collision integral in the Landau transport equation for quasiparticles.

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arXiv2003

Hadron Multiplicity in Semi-Inclusive Lepton-Nucleon and Lepton-Nucleus Scattering

We discuss multi-hadron production in both inelastic neutrino-nucleon interactions in the current fragmentation region and neutrino-nucleus collisions in the target fragmentation region. Our analysis, carried out within the framework of the quark-gluon string model, is mainly focused on the difference between these two processes. We show that the $Q^2$ dependence of hadron multiplicity in the current and target fragmentation regions is indeed completely different. The study of inelastic $ν-A$ scattering in the target fragmentation region also provides new information on nuclear structure at small $N-N$ distances. The results of the proposed approach are in satisfactory agreement with the data recently obtained at CERN by the NOMAD Collaboration.

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arXiv2003

Deuteron distribution in nuclei and the Levinger's factor

We compute the distribution of quasideuterons in doubly closed shell nuclei. The ground states of $^{16}$O and $^{40}$Ca are described in $ls$ coupling using a realistic hamiltonian including the Argonne $v_{8}^\prime$ and the Urbana IX models of two-- and three--nucleon potentials, respectively. The nuclear wave function contains central and tensor correlations, and correlated basis functions theory is used to evaluate the distribution of neutron-proton pairs, having the deuteron quantum numbers, as a function of their total momentum. By computing the number of deuteron--like pairs we are able to extract the Levinger's factor and compare to both the available experimental data and the predictions of the local density approximation, based on nuclear matter estimates. The agreement with the experiments is excellent, whereas the local density approximation is shown to sizably overestimate the Levinger's factor in the region of the medium nuclei.

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