Henryk Niewodniczanski Institute of Nuclear Physics PAN

Kraków, Poland

Henryk Niewodniczanski Institute of Nuclear Physics PAN

Kraków, Poland
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Begun V.,Warsaw University of Technology | Florkowski W.,Jan Kochanowski University | Ryblewski R.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2017

A Gribov-type dispersion relation is treated as an effective description of interacting gluons forming a hot medium. Temperature dependence of the Gribov parameter is determined from the fit to the lattice Yang-Mills results describing thermodynamic functions. To maintain thermodynamic consistency of the approach, a temperature-dependent bag pressure is introduced. The results obtained for equilibrium functions are generalised in the next step to non-equilibrium conditions. We derive formulas for the bulk and shear viscosity coefficients within the relaxation time approximation. We find evidence for largely enhanced bulk viscosity in the region of the phase transition.


Arriola E.R.,University of Granada | Broniowski W.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Broniowski W.,Jan Kochanowski University | Masjuan P.,Johannes Gutenberg University Mainz
Acta Physica Polonica B, Proceedings Supplement | Year: 2013

We suggest using the half-width rule to make an estimate of the 1/N c errors in hadronic models containing resonances. We show simple consequences ranging from the analysis of meson Regge trajectories, the hadron resonance gas at finite temperature and generalized hadronic form factors.


Maciula R.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Van Hameren A.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Szczurek A.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Szczurek A.,University of Rzeszow
Acta Physica Polonica B | Year: 2014

We discuss production of open charm mesons in proton-proton collisions at the LHC. The cross section for inclusive production of c-c pairs is calculated within the k⊥-factorization approach in which a major part of higher-order corrections is believed to be effectively included. We use and test the applicability of several unintegrated gluon distributions. Numerical results of the k⊥-factorization approach are compared to NLO pQCD collinear predictions. Inclusive differential distributions in transverse momentum and (pseudo)rapidity of several charmed mesons are presented and compared to recent results of the ALICE, ATLAS and LHCb collaborations. We also examine production of neutral charmed meson-antimeson pairs (D0D0) in unique kinematics of forward rapidities of the LHCb experiment. Kinematical correlations in azimuthal angle φD0D 0 , invariant mass D0D 0 and rapidity difference YD0D0 distributions are calculated. Moreover, we also discuss production of two pairs of c̄c within a simple formalism of double-parton scattering (DPS). We compare results of calculations of single-parton scattering (SPS) and double-parton scattering (DPS) for production of c̄cc̄c and for D0-D0 meson-meson correlations. We compare our predictions for double charm production with recent results of the LHCb Collaboration for azimuthal angle φD0D0 distribution, dimeson invariant mass MD0D0 and rapidity distance between mesons YD0D0 . The obtained results clearly certify the dominance of DPS in the production of events with double charm.


Malecki P.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2014

This article presents recent results obtained by the ATLAS experiment at the Large Hadron Collider (LHC) regarding the measurements of Standard Model and Flavor Physics phenomena performed with data collected in proton-proton collisions at center-of-mass energies √ s = 7 TeV and 8 TeV. Presented results include measurements of W and Z boson properties as well as selected QCD phenomena. Finally, a selection of results from the B-physics sector is shown.


Rachwal B.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2014

Lepton number is conserved in the Standard Model, therefore, any evidence for its violation would indicate the existence of New Physics models. This paper presents selected searches of rare decays performed by the LHCb experiment. An update for the studies dedicated to on-shell Majorana neutrinos coupling to muons in the B- → π +μ -μ - decay channel is also presented.


Zabinski B.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2014

This note describes ATLAS results on multiplicity of produced charged particles in p+Pb collisions at the centre-of-mass energy of 5.02 TeV. The charged particle density was measured in a wide pseudorapidity range as a function of the collision centrality using 2.1 million events which were collected during a "pilot run" in September 2012. Analysis methods, centrality determination and the particle production dependence on the number of nucleons participating in the collisions are presented.


Bozek P.,AGH University of Science and Technology | Bozek P.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Broniowski W.,Henryk Niewodniczanski Institute of Nuclear Physics PAN | Broniowski W.,Jan Kochanowski University
Acta Physica Polonica B | Year: 2014

We discuss the use of the hydrodynamic model for the description of the evolution of dense matter formed in ultrarelativistic heavy-ion collisions. The collective flow observed in heavy-ion collisions at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider is consistent with the assumption that a fireball of strongly interacting matter is formed. Experimental results from p-Pb and d-Au collisions show similar phenomena, which suggests that collective expansion appears in small systems as well. We review the recent application of the hydrodynamic model to small systems and discuss limitations and possible further checks of this scenario.


Lewandowska E.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2014

Double parton distribution functions (DPDFs) are used in the description of double parton scattering. Their QCD evolution equations, known in the leading logarithmic approximation, obey non-trivial momentum and valence quark number sum rules. In this paper, we discuss the QCD evolution of the DPDFs, in particular, the specification of initial conditions for the evolution equations which obey the new momentum sum rules. We also present results on factorization of DPDFs on the product of two single parton distributions.


Matyja A.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2014

We present selected results devoted to the global properties of dense matter produced in the Pb-Pb collisions at √sNN = 2:76 TeV measured by the ALICE Collaboration. Several first results on p-Pb collisions at p sNN = 5:02 TeV related to the double ridge structure, identified transverse momentum particle spectra and baryon-to-meson ratio are briefly reviewed. Nuclear modification factor for charged hadrons, identified light and heavy flavors are discussed together with the studies on reconstructed jets.


Derendarz D.,Henryk Niewodniczanski Institute of Nuclear Physics PAN
Acta Physica Polonica B | Year: 2010

Relativistic heavy ion collisions at the LHC will uncover properties of a hot and dense medium formed at a collision energy thirty times larger than the energy presently available at RHIC. ATLAS is one of the three experiments participating in the heavy ion program at the LHC. A brief overview of the variety of observables which will be measured by ATLAS to study soft and hard QCD phenomena in heavy ion environment is presented. In particular the detector will measure global observables like charged particle multiplicity, azimuthal anisotropy and energy flow. The detector provides also an excellent capability to probe the quark gluon plasma by measurement of high energy jets and photons as well as quarkonia states. Performance of a high granularity calorimeter, silicon tracking detector and muon spectrometer in heavy ion collisions is reported. The unique ATLAS potential to study Pb+Pb interactions is discussed.

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