Univerzita Mateja Bela

Banská Bystrica, Slovakia

Univerzita Mateja Bela

Banská Bystrica, Slovakia
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Feckova Z.,Univerzita Pavla Jozefa Safarika | Steinheimer J.,Goethe University Frankfurt | Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University | Bleicher M.,Goethe University Frankfurt
Physical Review C - Nuclear Physics | Year: 2015

We explore the influence of deuteron formation in the late stage of nucleus-nucleus reactions on the fluctuations observed in the final net-proton yields around midrapidity. At each investigated energy, the produced (anti)proton yield at chemical freeze-out is assumed to fluctuate according to a Poisson distribution and in each event the probability for deuteron formation by coalescence is proportional to (dNproton/dy)2. The protons that are then clustered in deuterons are usually not included in the experimental measurement of the net-proton fluctuations, therefore, we subtract these clustered protons from the final state proton number for the calculation of the net-proton fluctuations (the same is done in the antiproton sector). Due to the nonlinear deuteron formation probability the resulting distribution is not a Skellam distribution, but shows the interesting feature of a decrease in the kurtosis κσ2 and a local maximum in the skewness Sσ observables as the collision energy decreases. © 2015 American Physical Society.

Melo I.,University of Zilina | Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University
Journal of Physics: Conference Series | Year: 2016

We report our results for the freeze-out temperature and transverse flow profile obtained from fits to hadronic spectra measured by the ALICE collaboration. The influence of resonance decays is important and cannot be simply accounted for without the inclusion of their decays into the fits.

Bozek P.,University of Rzeszow | Bozek P.,Polish Academy of Sciences | Chojnacki M.,Polish Academy of Sciences | Florkowski W.,Polish Academy of Sciences | And 3 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

Using the newest data for pp scattering at the CERN Large Hadron Collider (LHC) combined with the Glauber model, we make hydrodynamic predictions for the soft hadronic observables planned to be measured in the forthcoming Pb. +. Pb collisions at sNN=2.76 TeV. © 2010 Elsevier B.V.

Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University | Kolomeitsev E.E.,Univerzita Mateja Bela
Journal of Physics: Conference Series | Year: 2016

We present a minimal statistical model designed for the description of rare- hadron multiplicities in nucleus-nucleus collisions at energies below the threshold of the particle production in binary elementary collisions. Differences to more conventional canonical statistical model are explained. The minimal statistical model is applied to the description of multiplicity ratios involving Ξ hyperons, which are measured by the HADES collaboration at GSI-SIS. It is argued that the HADES data cannot be reproduced by the model based on the statistical equilibrium and the strangeness conservation. The data remain underpredicted even when inmedium potentials acting on hadrons are taken into account. This hints to non-equilibrium production of the Ξ hyperons and their continuous freeze-out.

Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University
Computer Physics Communications | Year: 2016

The Monte Carlo generator DRAGON simulates hadron production in ultrarelativistic nuclear collisions. The underlying theoretical description is provided by the blast-wave model. DRAGON includes second-order angular anisotropy in transverse shape and the amplitude of the transverse expansion velocity. It also allows to simulate hadron production from a fragmented fireball, e.g. as resulting from spinodal decomposition happening at the first-order phase transition. New version program summary Program Title: DRAGON Program Files doi:10.17632/pcx8rk4wj5.1 Licensing provisions: GNU General Public License 3 Programming language: C++ Journal reference of previous version: Computer Physics Communication 180 (2009) 1642 Does the new version supersede the previous version?: Yes in the used algorithms, not in physics. Nature of problem: Deconfined matter produced in ultrarelativistic nuclear collisions expands and cools down and eventually returns into the confined phase. If the expansion is fast, the fireball could fragment either due to spinodal decomposition [1] or due to suddenly arising bulk viscous force [2]. Particle abundances are reasonably well described with just a few parameters within the statistical approach. Momentum spectra integrated over many events can be interpreted as produced from an expanding and locally thermalised fireball. The present Monte Carlo model unifies these approaches: fireball decays into fragments of some characteristic size. The fragments recede from each other as given by the pre-existing expansion of the fireball. They subsequently emit stable and unstable hadrons with momenta generated according to thermal distribution. Resonances then decay and their daughters acquire momenta as dictated by decay kinematics. If the fireball does not fragment, all hadrons are produced from the bulk as described by the blast-wave model [3]. Solution method: The Monte Carlo generator repeats a loop in which it generates individual events. First, sizes of fragments are generated. Then the fragments are placed within the decaying fireball and their velocities are determined from the one-to-one correspondence between the position and the expansion velocity in the blast wave model. Since hadrons may be emitted from fragments as well as from the remaining bulk fireball, first those from the bulk are generated according to the blast wave model. Then, hadron production from the fragments is treated. Each hadron is generated in the rest frame of the fragment and then boosted to the global frame. Finally, after all directly produced hadrons are generated, resonance decay channels are chosen and the momenta and positions of final state hadrons are determined. Reasons for the new version:* The main reason for the new version is the slow performance and precision errors in the procedure for the determination of particle types. We also fixed some bugs which had small effect on the determination of the momenta. Summary of revisions:* The calculation of the probabilities of different types of hadrons and resonance species has been completely rewritten. Before, this calculation was a major time consumer at the beginning of the running and also was less precise. The new routines use the method for calculation of density integrals proposed in [4]. A new procedure for the determination of momenta has been introduced. Previous version included deviations from the proper quantum-statistical distributions; this was investigated and documented in the original paper. In the new version we solved the problem how to efficiently generate momenta [5]. The generated values are drawn now exactly from the Fermi–Dirac or Bose–Einstein distribution, and practically any allowed value of the chemical potential is feasible. The algorithm uses rejection method with acceptance probability better than 90%. Some bugs connected with incorrect use of the Cooper–Frye formula [6] have been fixed. The output has been checked against calculable spectra where they can be determined. Finally, we introduced a new long int variable grandma into the class Particle. For every hadron which comes from a resonance decay, it stores the ID of the original resonance at the beginning of the decay chain. It assumes the value 0 for directly produced hadrons. This allows to trace the origin of the hadrons and judge about the importance of higher resonances. Restrictions: none Unusual features: none Additional comments: none Running time: Depends on the required number of events to be generated and on the values of the parameters. The test run with the default setting which generates 500 events corresponding to 2 units of rapidity in Au+Au collisions at top RHIC energy with no drops takes about 1 minute on MacBook Pro with 2.9 GHz Intel Core i7 with OSX 10.11.5 (El Capitan). [1] I. N. Mishustin, Nonequilibrium phase transition in rapidly expanding QCD matter, Phys. Rev. Lett. 82 (1999) 4779–4782. arXiv:hep-ph/9811307, http://dx.doi.org/10.1103/PhysRevLett.82.4779.[2] G. Torrieri, B. Tomášik, I. Mishustin, Bulk viscosity driven clusterization of quark–gluon plasma and early freeze-out in relativistic heavy-ion collisions, Phys. Rev. C77 (2008) 034903. arXiv:0707.4405, http://dx.doi.org/10.1103/PhysRevC.77.034903.[3] F. Retiere, M. A. Lisa, Observable implications of geometrical and dynamical aspects of freeze out in heavy ion collisions, Phys. Rev. C70 (2004) 044907. arXiv:nucl-th/0312024, http://dx.doi.org/10.1103/PhysRevC.70.044907.[4] S. M. Johns, P. J. Ellis, J. M. Lattimer, Numerical approximation to the thermodynamic integrals, Astrophys. J. 473 (1996) 1020–1028. arXiv:nucl-th/9604004, http://dx.doi.org/10.1086/178212.[5] B. Tomášik, I. Melo, J. Cimerman, Generation of random deviates for relativistic quantum-statistical distributions arXiv:1602.08233.[6] F. Cooper, G. Frye, Comment on the Single Particle Distribution in the Hydrodynamic and Statistical Thermodynamic Models of Multiparticle Production, Phys. Rev. D10 (1974) 186. http://dx.doi.org/10.1103/PhysRevD.10.186. © 2016 Elsevier B.V.

Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University | Kolomeitsev E.E.,Univerzita Mateja Bela
Acta Physica Polonica B, Proceedings Supplement | Year: 2012

We investigate production of φ mesons and Ξ baryons in nucleus-nucleus collisions. Reactions on strange particles acting as a catalyser are proposed to interpret the high observed φ yields in HADES experiments as well as the energy dependence of the widths of φ rapidity spectra in collisions at the SPS energies. It is argued that the enhancement of Ξ - yield observed by HADES is even higher than originally reported, if effects of the experimental centrality trigger are taken into account. Cross sections for new hadronic processes that could produce Ξ - are reviewed.

Kolomeitsev E.E.,Univerzita Mateja Bela | Tomasik B.,Univerzita Mateja Bela | Tomasik B.,Czech Technical University | Voskresensky D.N.,National Research Nuclear University MEPhI
Physical Review C - Nuclear Physics | Year: 2012

The High Acceptance Di-Electron Spectrometer (HADES) data on strangeness production in Ar + KCl collisions at 1.76A GeV are analyzed within a minimal statistical model. In the model the total negative strangeness content is fixed by the observed K+ multiplicities. Particles with negative strangeness are assumed to remain in chemical equilibrium with themselves and in thermal equilibrium with the environment until a common freeze-out. Exact strangeness conservation in each collision event is explicitly preserved. This implies that Ξ baryons can be released only in events where two or more kaons are produced. An increase of the fireball volume due to application of a centrality trigger in HADES experiments is taken into account. We find that experimental ratios of Kâ̂/K+, Λ/K +, and Σ/K+ can be satisfactorily described provided in-medium potentials are taken into account. However, the calculated Ξâ̂/Λ/K+ ratio proves to be significantly smaller compared to the measured value (eight times less than the experimental median value and three times less than the lower error bar). Various scenarios to explain observed Ξ enhancement are discussed. Arguments are given in favor of the Ξ production in direct reactions. The rates of the possible production processes are estimated and compared. © 2012 American Physical Society.

Prevalence of functional disorders of the musculoskeletal apparatus in the school population is a precondition for structural changes and often the cause of invalidity in adulthood in Slovakia. Also statistics of health insurance companies correspond with this fact. Therefore, early diagnosis and prevention in children and youth carried out through exercise programs are one of the options of prevention of these facts in later age. The study presents a partial objective and tasks with the intention of the intervention exercise programme to influence selected determinants of the muscul oskeletal system in female pupils of fourth grades at secondary schools within lessons of physical education, with the possibility to extend the knowledge about the effect and significance of exercise programs as a part of physical education. Our selected test group consisted of female fourth grade pupils at secondary schools in L. Mikuláš. As to methods for obtaining data we used standardized methods of evaluation of selected musculoskeletal apparatus determinants based on pedagogical and medical practice. We processed the obtained qualitative and quantitative data of evaluation of the dynamic function of the spine with the aid of the parametric t-test for dependent observation and the Chi-square test for overall muscle balance. Results significantly (p < 0.01) demonstrated the impact of the selected exercise program with selected equipment on the determinants of the muscular system in the tested group of female pupils, whereby we confirmed the effectiveness of the exercise program on spine dynamic function and overall muscle balance, as well as of the possibilities of its inclusion in physical education and sports.

Madlenak T.,Univerzita Mateja Bela
Geograficky Casopis | Year: 2010

Electoral geography has been established as an important part of political geography in the post-communist countries of Central and Eastern Europe in the last twenty years. Geographers endeavour to contribute to increasing electoral studies focusing on the spatial context of elections. The aim of this article is to identify the main research trends in current electoral geography around the world. We emphasize the approaches of relevant researchers to electoral geography's most important issues. The article offers a basic review of contemporary leading studies and the main research directions in electoral geography. © Institute of Geography SAS.

The paper deals with changes in water volumes contained in the Halčiansky water reservoir as a result of sedimentation and aggradation of bed loads and wash loads to the area of a water reservoir by the influence of erosive activity of tributaries in the watershed. The results of a comparison of two 3D models, one for the year 1908, created from historic documentation, and the other for year 2010, created from collection of data in the field, have shown a reduction in the volume of water totaling 35,874 m3, which represents the volume of sediments accumulated over the period of 102 years. Modern surveying technology and numerical modeling of the selected watershed surface area have been used for the determination of the changes in water volume. Analysis of secondary landscape structures, slope and empirical knowledge were performed in basin areas prone to erosion, in order to further the understanding of factors contributing to the erosion of the material. Water management, forestry, agriculture and population level, build-up of the area have all been identified as contributing elements, alongside other factors. © Česká geografická společnost, 2014.

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