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Papers by Grigory Feofilov
Physical Review Letters, 2013
We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at √ sNN = 2.7... more We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at √ sNN = 2.76 TeV, measured with the ALICE detector at the CERN Large Hadron Collider. The dynamical fluctuations per unit entropy are observed to decrease when going from peripheral to central collisions. An additional reduction in the amount of fluctuations is seen in comparison to the results from lower energies. We examine the dependence of fluctuations on the pseudo-rapidity interval, which may account for the dilution of fluctuations during the evolution of the system. We find that the ALICE data points are between the theoretically predicted values for a hadron gas and a Quark-Gluon Plasma.
The ALICE Collaboration xii Chapter ' 65 µm. This layer has a thickness of ' 1.4 % of radiation l... more The ALICE Collaboration xii Chapter ' 65 µm. This layer has a thickness of ' 1.4 % of radiation length in the central part (at zero pseudorapidity), and it is placed at similar radial distance from the interaction point as the current innermost ALICE layer. The thickness of the silicon part of the ATLAS tracker at mid-rapidity is ' 20 % and together with Transition Radiation Tracker ' 40 % of radiation length. After the upgrade [4] (phase 1) of the CMS pixel detector, the resolution in the distance of closest approach will be s 1GeV rj = 60-65 µm at pseudorapidities h = 0.0-1.0. The four-layer pixel detector will have thickness ' 7 %
Journal of High Energy Physics, 2013
We present the measurements of particle pair yields per trigger particle obtained from di-hadron ... more We present the measurements of particle pair yields per trigger particle obtained from di-hadron azimuthal correlations in pp collisions at $ \sqrt{s} $ = 0.9, 2.76, and 7 TeV recorded with the ALICE detector. The yields are studied as a function of the charged particle multiplicity. Taken together with the single particle yields the pair yields provide information about parton fragmentation at low transverse momenta, as well as on the contribution of multiple parton interactions to particle production. Data are compared to calculations using the PYTHIA6, PYTHIA8, and PHOJET event generators.
Physical Review Letters, 2013
General rights Copyright and moral rights for the publications made accessible in the public port... more General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Авторы выражают благодарность гранту Санкт-Петербургского государственного университета 11.38.242... more Авторы выражают благодарность гранту Санкт-Петербургского государственного университета 11.38.242.2015. Работа В. Н. Коваленко была выполнена при поддержке специальной ректорской стипендии СПбГУ, гранта фонда «Династия» и стипендии G-RISC.
Journal of Physics: Conference Series, 2016
In this report we present the motivation and general design of a new vertex detector (VD) for NA6... more In this report we present the motivation and general design of a new vertex detector (VD) for NA61/SHINE. Several practical solutions to meet the requirements for this VD are proposed and demonstrated.
Journal of Physics: Conference Series, 2016
Cern Courier Vol 52 No 10 December 2012, Sep 14, 2012
Cern Courier Vol 52 No 10 December 2012, Sep 14, 2012
Particle Physics at the Tercentenary of Mikhail Lomonosov, 2013
AIP Conference Proceedings, 2012
The experimental studies of long-range correlations (LRC) starting from pp collisions at the ISR ... more The experimental studies of long-range correlations (LRC) starting from pp collisions at the ISR to hadron collisions at RHIC and LHC, as well as some major theoretical motivations, are presented. We discuss, basing on MC PYTHIA, HIJING and String Fusion Model (SFM) analysis, some possible manifestations of collective effects both in Pb-Pb and pp collisions in a broad energy range. Finally, a brief outlook for the LRC studies, currently performed by ALICE in Pb-Pb and pp collisions at the LHC, is given.
Bulletin of the Russian Academy of Sciences: Physics, 2019
Dependences of the average transverse momentum of charged particles on rapidity and pseudorapidit... more Dependences of the average transverse momentum of charged particles on rapidity and pseudorapidity are obtained, and the influence the effects of color reconnection and the formation of hadronic jets have on these dependences is studied. It is shown that the result depends largely on the interval of which physical quantity (rapidity or pseudorapidity) particle distributions over the transverse momentum are considered. It is important to compare theoretically calculated distributions to experimental data. It is shown in particular that allowing for the kinematic factor which arises in describing the distribution of particles over the transverse momentum in the specified pseudorapidity interval considerably influences the description of experimental data on pp-collisions at energies of TeV in the Large Hadron Collider.
A new variant of the effective pomeron exchange model is proposed for the description of the corr... more A new variant of the effective pomeron exchange model is proposed for the description of the correlation, observed in pp and pp collisions at center-of-mass energy from SPS to LHC, between mean transverse momentum and charged particles multiplicity. The model is based on the Regge-Gribov approach. Smooth logarithmic growth with the collision energy was established for the parameter k, the mean rapidity density of charged particles produced by a single string. It was obtained in the model by the fitting of the available experimental data on charged particles rapidity density in pp and pp collisions. The main effect of the model, a gradual onset of string collectivity with the growth of collision energy, is accounted by a free parameter β that is responsible in an effective way for the string fusion phenomenon. Another free parameter, t, is used to define string tension. We extract parameters β and t from the available experimental results on p tmultiplicity correlation at nucleon collision energy √ s from 17 GeV to 7 TeV. Smooth dependence of both β and t on energy allows to make predictions for the correlation behavior at the collision energy of 14 TeV. The indications to the string interaction effects in high multiplicity events in pp collisions at the LHC energies are also discussed.
Constraints on string percolation model from anomalous centrality evolution data in Au-Au collisi... more Constraints on string percolation model from anomalous centrality evolution data in Au-Au collisions at sNN = 62 and 200 GeV
![Research paper thumbnail of Centrality determination of Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV with ALICE](https://attachments.academia-assets.com/82749295/thumbnails/1.jpg)
](Physical Review C, 2013
This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisio... more This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection, and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.
The European Physical Journal C-Particles and Fields, 2010
On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), tw... more On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in ...
Physical Review Letters, 2013
We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at √ sNN = 2.7... more We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at √ sNN = 2.76 TeV, measured with the ALICE detector at the CERN Large Hadron Collider. The dynamical fluctuations per unit entropy are observed to decrease when going from peripheral to central collisions. An additional reduction in the amount of fluctuations is seen in comparison to the results from lower energies. We examine the dependence of fluctuations on the pseudo-rapidity interval, which may account for the dilution of fluctuations during the evolution of the system. We find that the ALICE data points are between the theoretically predicted values for a hadron gas and a Quark-Gluon Plasma.
The ALICE Collaboration xii Chapter ' 65 µm. This layer has a thickness of ' 1.4 % of radiation l... more The ALICE Collaboration xii Chapter ' 65 µm. This layer has a thickness of ' 1.4 % of radiation length in the central part (at zero pseudorapidity), and it is placed at similar radial distance from the interaction point as the current innermost ALICE layer. The thickness of the silicon part of the ATLAS tracker at mid-rapidity is ' 20 % and together with Transition Radiation Tracker ' 40 % of radiation length. After the upgrade [4] (phase 1) of the CMS pixel detector, the resolution in the distance of closest approach will be s 1GeV rj = 60-65 µm at pseudorapidities h = 0.0-1.0. The four-layer pixel detector will have thickness ' 7 %
Journal of High Energy Physics, 2013
We present the measurements of particle pair yields per trigger particle obtained from di-hadron ... more We present the measurements of particle pair yields per trigger particle obtained from di-hadron azimuthal correlations in pp collisions at $ \sqrt{s} $ = 0.9, 2.76, and 7 TeV recorded with the ALICE detector. The yields are studied as a function of the charged particle multiplicity. Taken together with the single particle yields the pair yields provide information about parton fragmentation at low transverse momenta, as well as on the contribution of multiple parton interactions to particle production. Data are compared to calculations using the PYTHIA6, PYTHIA8, and PHOJET event generators.
Physical Review Letters, 2013
General rights Copyright and moral rights for the publications made accessible in the public port... more General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Авторы выражают благодарность гранту Санкт-Петербургского государственного университета 11.38.242... more Авторы выражают благодарность гранту Санкт-Петербургского государственного университета 11.38.242.2015. Работа В. Н. Коваленко была выполнена при поддержке специальной ректорской стипендии СПбГУ, гранта фонда «Династия» и стипендии G-RISC.
Journal of Physics: Conference Series, 2016
In this report we present the motivation and general design of a new vertex detector (VD) for NA6... more In this report we present the motivation and general design of a new vertex detector (VD) for NA61/SHINE. Several practical solutions to meet the requirements for this VD are proposed and demonstrated.
Journal of Physics: Conference Series, 2016
Cern Courier Vol 52 No 10 December 2012, Sep 14, 2012
Cern Courier Vol 52 No 10 December 2012, Sep 14, 2012
Particle Physics at the Tercentenary of Mikhail Lomonosov, 2013
AIP Conference Proceedings, 2012
The experimental studies of long-range correlations (LRC) starting from pp collisions at the ISR ... more The experimental studies of long-range correlations (LRC) starting from pp collisions at the ISR to hadron collisions at RHIC and LHC, as well as some major theoretical motivations, are presented. We discuss, basing on MC PYTHIA, HIJING and String Fusion Model (SFM) analysis, some possible manifestations of collective effects both in Pb-Pb and pp collisions in a broad energy range. Finally, a brief outlook for the LRC studies, currently performed by ALICE in Pb-Pb and pp collisions at the LHC, is given.
Bulletin of the Russian Academy of Sciences: Physics, 2019
Dependences of the average transverse momentum of charged particles on rapidity and pseudorapidit... more Dependences of the average transverse momentum of charged particles on rapidity and pseudorapidity are obtained, and the influence the effects of color reconnection and the formation of hadronic jets have on these dependences is studied. It is shown that the result depends largely on the interval of which physical quantity (rapidity or pseudorapidity) particle distributions over the transverse momentum are considered. It is important to compare theoretically calculated distributions to experimental data. It is shown in particular that allowing for the kinematic factor which arises in describing the distribution of particles over the transverse momentum in the specified pseudorapidity interval considerably influences the description of experimental data on pp-collisions at energies of TeV in the Large Hadron Collider.
A new variant of the effective pomeron exchange model is proposed for the description of the corr... more A new variant of the effective pomeron exchange model is proposed for the description of the correlation, observed in pp and pp collisions at center-of-mass energy from SPS to LHC, between mean transverse momentum and charged particles multiplicity. The model is based on the Regge-Gribov approach. Smooth logarithmic growth with the collision energy was established for the parameter k, the mean rapidity density of charged particles produced by a single string. It was obtained in the model by the fitting of the available experimental data on charged particles rapidity density in pp and pp collisions. The main effect of the model, a gradual onset of string collectivity with the growth of collision energy, is accounted by a free parameter β that is responsible in an effective way for the string fusion phenomenon. Another free parameter, t, is used to define string tension. We extract parameters β and t from the available experimental results on p tmultiplicity correlation at nucleon collision energy √ s from 17 GeV to 7 TeV. Smooth dependence of both β and t on energy allows to make predictions for the correlation behavior at the collision energy of 14 TeV. The indications to the string interaction effects in high multiplicity events in pp collisions at the LHC energies are also discussed.
Constraints on string percolation model from anomalous centrality evolution data in Au-Au collisi... more Constraints on string percolation model from anomalous centrality evolution data in Au-Au collisions at sNN = 62 and 200 GeV
Physical Review C, 2013
This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisio... more This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection, and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.
The European Physical Journal C-Particles and Fields, 2010
On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), tw... more On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in ...