V. Antonenko

Kurchatov Institute, Moskva, Moscow, Russia

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Publications (140)

  • Source
    Full-text Dataset · Jun 2014
  • Dataset · Jan 2013
  • [Show abstract] [Hide abstract] ABSTRACT: Measurements of direct photon production in p+Pb and p+C collisions at √sNN=17.4 GeV are presented. Upper limits on the direct photon yield as a function of pT are derived and compared to the results for Pb+Pb collisions at √sNN=17.3 GeV. The production of the η meson, which is an important input to the direct photon signal extraction, has been determined in the η → 2γ channel for p+C collisions at √sNN=17.4 GeV.
    Article · Jan 2013
  • Article · Jul 2011
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    [Show abstract] [Hide abstract] ABSTRACT: Charged particles and photons have been measured in central Pb+Pb collisions at 158 A GeV in a common ($\eta$ - $\phi$)-phase space region in the WA98 experiment at the CERN SPS. The measured distributions have been analyzed %using the sliding window method in order to quantify the frequency with which phase space regions of varying sizes have either small or large neutral pion fraction. The measured results are compared with VENUS model simulated events and with mixed events. Events with both large and small charged-neutral fluctuations are observed to occur more frequently than expected statistically, as deduced from mixed events, or as predicted by model simulations, with the difference becoming more prominent with decreasing size of the $\Delta\eta$ - $\Delta\phi$ region.
    Full-text Article · Mar 2011
  • [Show abstract] [Hide abstract] ABSTRACT: New experimental results on ratio R dp of the quasielastic charge-exchange yield at the outgoing proton angle θ p,lab = 0° for the nd → p(nn) reaction to the elastic np → pn charge-exchange yield, are presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron-beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8, and 2.0 GeV. The intense neutron beam with small momentum spread was produced by breakup of deuterons which were accelerated and extracted to the experimental hall. In both reactions mentioned above the outgoing protons with the momenta p p approximately equal to the neutron-beam momentum p n,beam were detected in the directions close to the direction of incident neutrons, i.e., in the vicinity of the scattering angle θ p,lab = 0°. Measured in the same data-taking runs, the angular distributions of the charge-exchange-reaction products were corrected for the well-known instrumental effects and averaged in the vicinity of the incident-neutron-beam direction. These corrected angular distributions for every of nd → p(nn) and np → pn charge-exchange processes were proportional to the differential cross sections of the corresponding reactions. The data were accumulated by Delta-Sigma setup magnetic spectrometer with two sets of multiwire proportional chambers located upstream and downstream of the momentum analyzing magnet. Inelastic processes were considerably reduced by the additional detectors surrounding the hydrogen and deuterium targets. The time-of-flight system was applied to identify the detected particles. The accumulated data treatment and analysis, as well as possible sources of the systematic errors are discussed.
    Article · Jun 2009 · Physics of Atomic Nuclei
  • [Show abstract] [Hide abstract] ABSTRACT: New experimental results on the ratio Rdp of the quasi-elastic charge-exchange yield at the outgoing proton angle \( \theta_{{p,{\rm Lab}}}^{}\) = 0° for the nd \( \rightarrow\) p(nn) reaction to the elastic np \( \rightarrow\) pn charge-exchange yield are presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8 and 2.0GeV. The intense neutron beam with small momentum spread was produced by break-up of deuterons which were accelerated and extracted to the experimental hall. In both reactions mentioned above the outgoing protons with the momenta p p approximately equal to the neutron beam momentum p n, beam were detected in the directions close to the direction of incident neutrons, i.e. in the vicinity of the scattering angle \( \theta_{{p,{\rm Lab}}}^{}\) = 0° . Measured in the same data taking runs, the angular distributions of the charge-exchange reaction products were corrected for the well-known instrumental effects and averaged in the vicinity of the incident neutron beam direction. These corrected angular distributions for every of nd \( \rightarrow\) p(nn) and np \( \rightarrow\) pn charge-exchange processes were proportional to the differential cross-sections of the corresponding reactions. The data were accumulated by the Delta-Sigma set-up magnetic spectrometer with two sets of multiwire proportional chambers located upstream and downstream of the momentum analyzing magnet. Inelastic processes were considerably reduced by the additional detectors surrounding the hydrogen and deuterium targets. The time-of-flight system was applied to identify the detected particles. The new Rdp data are compared with the existing ones, which were obtained below 1GeV, and with the calculations which were made using the phenomenological NN amplitude sets.
    Article · Jan 2009 · European Physical Journal A
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    [Show abstract] [Hide abstract] ABSTRACT: ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 16 × 16 × 26 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
    Full-text Article · Aug 2008 · Journal of Instrumentation
  • L. N. Strunov · V. G. Antonenko · S. B. Borzakov · [...] · V. N. Zhmyrov
    [Show abstract] [Hide abstract] ABSTRACT: The measurements of np-spin observables at 0° have been performed for the first time on the Delta-Sigma experimental facility of LHE JINR up to P n = 4.5 GeV/c using the monochromatic neutron beam. They include detailed measurements of the Δσ L(np) spin differences and the study of the np → pn elastic charge-exchange process. In the Δσ L(np) and −Δσ L(I = 0) energy dependencies over the energy region Tkin = 1.2–3.7 GeV the peculiarity at 1.8 GeV was observed. Such energy behavior was predicted by the QCD approach as a signal of the NN → 6q phase transition. For the exhaustive investigation of this effect it is necessary to measure the energy dependence of the complete set of np observables with both longitudinal (L) and transverse (T) polarizations of the neutron beam and proton target. This will allow Direct Reconstruction of all three NN forward Scattering Amplitudes (DRSA) to be performed, and the observed peculiarity to be checked around Tkin = 1.8 GeV and at the higher energies using the Argand diagrams method.
    Article · Aug 2008 · The European Physical Journal Special Topics
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    [Show abstract] [Hide abstract] ABSTRACT: ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 16 × 16 × 26 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
    Full-text Article · Jul 2008
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    [Show abstract] [Hide abstract] ABSTRACT: Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt[S{NN}]=17.4 GeV at midrapidity (2.3 less than or approximately equal eta{lab} less than or approximately equal 3.0) over the range 0.7 less than or approximately equal p{T} less than or approximately equal 3.5 GeV/c. The spectra are compared to pi{0} spectra measured in Pb+Pb collisions at sqrt[S{NN}]=17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N{part} less than or approximately equal 300), the yield of pi{0}'s with p{T} greater than or approximately equal 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N{coll}), while for central Pb+Pb collisions with N{part}greater than or approximately equal 350, the pi{0} yield is suppressed.
    Full-text Article · Jun 2008 · Physical Review Letters
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    [Show abstract] [Hide abstract] ABSTRACT: The effect of the final state Coulomb interaction on particles produced in Pb+Pb collisions at 158 AGeV/c has been investigated in the WA98 experiment through the study of the π-/π+ and K-/K+ ratios measured as a function of mT-m0. While the ratio for kaons shows no significant mT dependence, the π-/π+ ratio is enhanced at small mT-m0 values with an enhancement that increases with centrality. A silicon pad detector located near the target is used to estimate the contribution of hyperon decays to the π-/π+ ratio. The comparison of results with predictions of the RQMD model in which the Coulomb interaction has been incorporated allows to place constraints on the time of the pion freeze-out.
    Full-text Article · Nov 2006 · European Physical Journal C
  • Article · Jan 2006
  • V. I. Sharov · V. G. Antonenko · S. B. Borzakov · [...] · V. N. Zhmyrov
    [Show abstract] [Hide abstract] ABSTRACT: New experimental results on the ratio R-dp of the charge-exchange quasi-elastic scattering yield at 0 degrees for the nd -> (nn) + p reaction to the elastic np -> np scattering yield are presented. These two charge -exchange angular dependences measured in a vicinity of the incident neutron direction, corrected for well known instrumental effects and extrapolated towards the incident neutron direction, are proportional to the differeiltial cross sections of the two relevant reactions. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research (JINR) at the neutron beam kinetic energies of 0.8, 1.0, 1.2, 1.4, 1.8 and 2.0 GeV. The intense quasi-monochromatic neutron beam was produced by break-up of accelerated deuterons extracted to the experimental area. The data were accumulated using the "Delta-Sigma" set-up magnetic spectrometer with two sets of multiwire proportional chambers, located upstream and downstream of the analyzing magnet. Inelastic processes were considerably reduced by detectors surrounding either the hydrogen, or deuterium targets. The time-of-flight system was used for detected particle identification. The data treatment and analysis of possible systematic errors are discussed. The obtained R-dp values remain nearly constant with energy. The new data are compared with existing ones, measured only at energies below 1 GeV.
    Conference Paper · Jan 2006
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    [Show abstract] [Hide abstract] ABSTRACT: Directed and elliptic flow of inclusive photons near mid-rapidity in 158 A GeV Pb + Pb collisions has been studied. The data have been obtained with the photon spectrometer LEDA of the WA98 experiment at the CERN SPS. The flow strength has been measured for various centralities as a function of pT and rapidity over 0.18<pT<1.5 GeV/c and 2.3<y<2.9. The angular anisotropy has been studied relative to an event plane obtained in the target fragmentation region that shows the elliptic flow to be in-plane. The elliptic flow has also been studied using two-particle correlations and shown to give similar results. A small directed flow component is observed. Both the directed and elliptic flow strengths increase with pT. The photon flow results are used to estimate the corresponding neutral pion flow.
    Full-text Article · Nov 2005 · Nuclear Physics A
  • Article · Nov 2005
  • V. I. Sharov · N. G. Anischenko · V. G. Antonenko · [...] · V. N. Zhmyrov
    [Show abstract] [Hide abstract] ABSTRACT: New accurate data of the neutron-proton spin-dependent total-cross-section difference Δσ L(np) at the neutron-beam kinetic energies 1.39, 1.69, 1.89, and 1.99 GeV are presented. In general, these data complete the measurements of energy dependence of Δσ L(np) over the Dubna Synchrophasotron energy region. Measurements were carried out at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. The quasi-monochromatic neutron beam was produced by breakup of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The initial transverse (with respect to beam momentum) neutron polarization was changed to a longitudinal one and longitudinally polarized neutrons were transmitted through the large proton longitudinally polarized target. The target polarization direction was inverted after one to two days of measurements. Four different combinations of the beam and target parallel and antiparallel polarization directions, both oriented along the neutron-beam momentum, were used at each energy. A fast decrease in −Δσ L(np) with increasing energy above 1.1 GeV and a structure in the energy dependence around 1.8 GeV, first observed from our previous data, seem to be well revealed. The new results are also compared with model predictions and with phase-shift analysis fits. The Δσ L quantities for isosinglet state I = 0, deduced from the measured Δσ L(np) values and known Δσ L(pp) data, are also given. The results of the measurements of unpolarized total cross sections σ 0tot(np) at 1.3, 1.4, and 1.5 GeV and σ 0tot(nC) at 1.4 and 1.5 GeV are presented as well. These data were obtained using the same apparatus and high-intensity unpolarized deuteron beams extracted either from the Synchrophasotron or from the Nuclotron.
    Article · Nov 2005 · Physics of Atomic Nuclei
  • A. A. Morozov · V. G. Antonenko · S. B. Borzakov · [...] · V. N. Zhmyrov
    [Show abstract] [Hide abstract] ABSTRACT: The first results of the measurement of 0o of the cross-section ratioR dp=0.50±0.02 in charge-exchange (np) reaction on H2/D2 targets at the neutron beam kinetic energie 1.0 GeV are presented. As a result the value of the ratio of non spin-flip to spin-flip contribution innp→pn charge-exchange at 0o r np→pn /nf/fl =0.33±0.03 was obtained.
    Article · Jan 2005 · Czechoslovak Journal of Physics
  • [Show abstract] [Hide abstract] ABSTRACT: The azimuthal distributions of photons and charged particles with respect to the event plane are investigated as a function of centrality in Pb + Pb collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The anisotropy of the azimuthal distributions is characterized using a Fourier analysis. For both the photon and charged particle distributions the first two Fourier coefficients are observed to decrease with increasing centrality. The observed anisotropies of the photon distributions compare well with the expectations from the charged particle measurements for all centralities.
    Article · Jan 2005
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    [Show abstract] [Hide abstract] ABSTRACT: ALICE PHASE EI SEP ACC S2I
    Full-text Article · Jan 2005

Publication Stats

1k Citations

Institutions

  • 1984-2009
    • Kurchatov Institute
      Moskva, Moscow, Russia
  • 2000-2008
    • Panjab University
      • Department of Physics
      Chandigarh, Chandīgarh, India
  • 2006
    • Charles University in Prague
      Praha, Praha, Czech Republic
  • 1994-2001
    • University of Groningen
      Groningen, Groningen, Netherlands
  • 1998
    • University of Münster
      Muenster, North Rhine-Westphalia, Germany
  • 1985-1996
    • Obninsk Institute of Atomic Energy
      Moskva, Moscow, Russia