Vladimir Skokov's homepage


Current Affiliation: 
    Riken-BNL Research Center
    Upton, NY 11973 

Contact information:
    Work phone number: +1-631-344-3795
    Email: VVSkokov.at.gmail.com
    







Research Interests: 

  • non-perturbative methods of quantum field theory, the exact (functional) renormalization group
  • finite temperature field theory
  • deconfinement and chiral aspects of Quantum Chromo-Dynamics (QCD) phase transitions, effective models of QCD at finite temperature and density
  • nonequilibrium field theory; transport properties, thermalization, non-perturbative particle production in coherent fields
  • renormalization group, critical statics and critical dynamics in vicinity of a phase transition
  • high energy QCD, structure of nuclei and hadrons, deep inelastic scattering, transverse momentum dependent parton distribution functions, three dimensional structure of nucleons and nuclei in momentum and configuration space; phenomenology of high-energy electron-proton/ion, hadron and heavy-ion collisions




Highlighted publications: 


"Conformal anomaly as a source of soft photons in heavy ion collisions"  in collaboration with G. Basar and  D. Kharzeev,  published in Phys. Rev. Lett. 

We proposed a mechanism for photon production in QGPs based on a well-known feature of QCD: the conformal anomaly. As a classical system, QCD possesses a 
conformal invariance which is broken by quantum effects. We
 showed that the 
anomalous breaking of this symmetry in the presence of strong magnetic fields can lead to a novel mechanism for photon production. We demonstrated that an estimate of the photons produced through this mechanism corresponds to known experimental signal for photon azimuthal anisotropy. 



A set of publication on collectivity in small systems
(1) "Azimuthal asymmetries and the emergence of “collectivity” from multi-particle correlations in high-energy pA collisions" in collaboration with A. Dumitru and L. McLerran, published in Phys. Lett. B.
(2) "High order cumulants of the azimuthal anisotropy in the dilute-dense limit:Connected graphs" 
(3) "Anisotropy of the semi-classical gluon field of a large nucleus at high energy" in collaboration with A. Dumitru 

We show how angular asymmetries ∼ cos 2φ can arise in dipole scattering at high energies. 
The main new ingredient is  the effects due to anisotropic fluctuations of the saturation momentum of the target, i.e. from a domain-like structure. We compute the two-particle azimuthal cumulant in this model including both one-particle factorizable as well as genuine two-particle non-factorizable contributions (the so-called Glasma graph) to the two-particle cross section. We find that only the fully factorizable contribution to the four-particle harmonic v42{4} is positive while all contributions from genuine two, three and four-particle correlations are negative. Our results 
strongly suggest that the glasma graph alone cannot describe the available experimental data at high multiplicities! 
 
In a single author article 2), I also explored the higher order cumulants and showed that in the framework of the glasma graph, every second v2{m} is complex starting from m=4. See the figure on the right. We explored the domain structure in the MV model and at small x by using the JIMWLK evolution equation in the follow up article (3). The results suggest that there is significant anisotropy in the initial state and it is not diluted by the evolution




A set of publications on magnetic field in heavy-ion collisions
(1) "Estimate of the magnetic field strength in heavy-ion collisions" in collaboration with A. Illarionov and V. Toneev
In this set of publications, the properties of the magnetic field created in heavy-ion collisions were explored. In (1), the collisions energy and the impact parameter dependence of the magnitude of the magnetic field was established for the first time. In (2), with Adam Bzdak, I showed that fluctuations of the magnetic field are large and may lead to 
many other significant effects. This finding eventually helped to understand the uranium-uranium collisions 
data: it was realized the assumption that a fully overlapping collision has a small magnetic field is too simplistic. In
 
(2), for the first time novel ideas and measurements of electric field in asymmetric collisions was discussed; these were later developed by Hirono, Hongo and Hirano. The lifetime of the magnetic field and the effect of electric 
conductivity  were explored in (3). For  the field magnitude about or above the
pion mass squared, it was shown that a realistic value of the electric conductivity does not significantly alter the lifetime of the magnetic field, see the figure on the right.