Z. Fodor - Academia.edu (original) (raw)

Papers by Z. Fodor

Physics Letters B, 2010

The inclusive charged particle transverse momentum distribution is measured in proton-proton coll... more The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at √ s = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|η| < 0.8) over the transverse momentum range 0.15 < p T < 10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |η| < 0.8 is p T INEL = 0.483 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c and p T NSD = 0.489 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger p T than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET.

Nuclear Physics A, 2009

... I.; Kalita, H.; Kämpfer, B.; Karasev, V.; Karavichev, O.; Karavicheva, T.; Karmanov, D.; Karp... more ... I.; Kalita, H.; Kämpfer, B.; Karasev, V.; Karavichev, O.; Karavicheva, T.; Karmanov, D.; Karpechev, E.; Kashif, EM; Kasinski, K.; Kaur, Manjit; Kazantsev ... C.; Schmidt, CJ; Schrader, C.; Schweda, K.; Scurtu, A.; Seddiki, S.; Seliverstov, D.; Semak, A.; Semennikov, A.; Senger, P.; Shao ...

Journal of Physics G: Nuclear and Particle Physics, 2006

The European Physical Journal Special Topics, 2008

After a general introduction on the Quark Gluon Plasma and a short overview of the experimental r... more After a general introduction on the Quark Gluon Plasma and a short overview of the experimental results obtained so far with heavy-ion collisions at the SPS and at the RHIC, the physics goals of the ALICE experiment at the LHC are presented.

Journal of Physics G: Nuclear and Particle Physics, 2004

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interac... more ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions at the LHC. It currently includes more than 900 physicists and senior engineers, from both nuclear and high-energy physics, from about 80 institutions in 28 countries. The experiment was approved in February 1997. The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2001 and construction has started for most detectors. Since the last comprehensive information on detector and physics performance was published in the ALICE Technical Proposal in 1996, the detector as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) will give an updated and comprehensive summary of the current status and performance of the various ALICE subsystems, including updates to the Technical Design Reports, where appropriate, as well as a description of systems which have not been published in a Technical Design Report. The PPR will be published in two volumes. The current Volume I contains: a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, relevant experimental conditions at the LHC, a short summary and update of the subsystem designs, and a description of the offline framework and Monte Carlo generators. Volume II, which will be published separately, will contain detailed simulations of combined detector performance, event reconstruction, and analysis of a representative sample of relevant physics observables from global event characteristics to hard processes.

Physical Review C, 2008

Multiplicity fluctuations of positively, negatively and all charged hadrons in the forward hemisp... more Multiplicity fluctuations of positively, negatively and all charged hadrons in the forward hemisphere were studied in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV. The multiplicity distributions and their scaled variances ω are presented in dependence of collision energy as well as of rapidity and transverse momentum. The distributions have bell-like shape and their scaled variances are in the range from 0.8 to 1.2 without any significant structure in their energy dependence. No indication of the critical point in fluctuations are observed. The string-hadronic model UrQMD significantly overpredicts the mean, but approximately reproduces the scaled variance of the multiplicity distributions. The predictions of the statistical hadron-resonance gas model obtained within the grand-canonical and canonical ensembles disagree with the measured scaled variances. The narrower than Poissonian multiplicity fluctuations measured in numerous cases may be explained by the impact of conservation laws on fluctuations in relativistic systems.

Physical Review C, 2014

Azimuthal emission patterns of K ± mesons have been measured in Ni + Ni collisions with the FOPI ... more Azimuthal emission patterns of K ± mesons have been measured in Ni + Ni collisions with the FOPI spectrometer at a beam kinetic energy of 1.91 A GeV. The transverse momentum pT integrated directed and elliptic flow of K + and K − mesons as well as the centrality dependence of pT-differential directed flow of K + mesons are compared to the predictions of HSD and IQMD transport models. The data exhibits different propagation patterns of K + and K − mesons in the compressed and heated nuclear medium and favor the existence of a kaon-nucleon in-medium potential, repulsive for K + mesons and attractive for K − mesons.

Acta Physica Polonica B - ACTA PHYS POL B, 2006

The NA49 fixed-target experiment studied high energy-density matter produced in nucleus-nucleus r... more The NA49 fixed-target experiment studied high energy-density matter produced in nucleus-nucleus reactions at the CERN SPS. In central Pb+Pb collisions at 158A GeV the energy density at the early stage substantially exceeds the threshold for quark deconfinement predicted by lattice QCD. The produced matter shows strong transverse and longitudinal flow. Ratios of yields of produced particles are approximately consistent with statistical equilibration. An energy scan through the SPS range revealed structure in the energy dependence of pi and K yields as well as of the inverse slopes of transverse mass distributions. These features suggest that a deconfined phase starts to be produced at around 30A GeV in central Pb+Pb collisions. The analysis of fluctuations and correlations has not yet provided evidence for the predicted critical point of QCD.

$Research paper thumbnail of Sideward flow of <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mi>K</mi><mo lspace="0em" rspace="0em">+</mo></msup></mrow><annotation encoding="application/x-tex">K^{+}</annotation></semantics></math>K+ in Ru+Ru and Ni+Ni reactions at SIS energies$

The mass distributions of baryon resonances populated in near-central collisions of Au on Au and ... more The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the p t spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distributions of resonances are obtained from the invariant masses of (p, π ±) pairs. With both methods the deduced mass distributions are shifted by an average value of −60 MeV/c 2 relative to the mass distribution of the free ∆(1232) resonance, the distributions descent almost exponentially towards mass values of 2000 MeV/c 2. The observed differences between (p, π −) and (p, π +) pairs indicate a contribution of isospin I = 1/2 resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities.

Progress in Particle and Nuclear Physics, 2004

Physics Letters B, 2005

We present measurements of the excitation function of elliptic flow at midrapidity in Au+Au colli... more We present measurements of the excitation function of elliptic flow at midrapidity in Au+Au collisions at beam energies from 0.09 to 1.49 GeV per nucleon. For the integral flow, we discuss the interplay between collective expansion and spectator shadowing for three centrality classes. A complete excitation function of transverse momentum dependence of elliptic flow is presented for the first time in this energy range, revealing a rapid change with incident energy below 0.4 AGeV, followed by an almost perfect scaling at the higher energies. The equation of state of compressed nuclear matter is addressed through comparisons to microscopic transport model calculations.

Physics Letters B, 2004

Cluster production is investigated in central collisions of Ca+Ca, Ni+Ni, 96 Zr+ 96 Zr, 96 Ru+ 96... more Cluster production is investigated in central collisions of Ca+Ca, Ni+Ni, 96 Zr+ 96 Zr, 96 Ru+ 96 Ru, Xe+CsI and Au+Au reactions at 0.4A GeV incident energy. We find that the multiplicity of clusters with charge Z ≥ 3 grows quadratically with the system's total charge and is associated with a mid-rapidity source with increasing transverse velocity fluctuations. When reduced to the same number of available charges, an increase of cluster production by about a factor of 5.5 is observed in the mid-rapidity region between the lightest system (Ca+Ca) and the heaviest one (Au+Au). The results, as well as simulations using Quantum Molecular Dynamics, suggest a collision process where droplets, i.e. nucleon clusters, are created in an expanding, gradually cooling, nucleon gas. Within this picture, expansion dynamics, collective radial flow and cluster formation are closely linked as a result of the combined action of nucleon-nucleon scatterings and the mean fields.

Physical Review Letters, 1992

... spaced intervals. In the fol-lowing we focus on the description of the semicentral and centra... more ... spaced intervals. In the fol-lowing we focus on the description of the semicentral and central events (PM3-PM5), where background contribu-tions amount to a maximum of 14% at PM3 and are therefore negligible. For these ...

Physical Review Letters, 2001

Physical Review Letters, 1995

Complete distributions of the light and intermediate mass fragments ( Z = 1-6) produced within th... more Complete distributions of the light and intermediate mass fragments ( Z = 1-6) produced within the polar angular range 1o&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;=Thetalab&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;=30o in highly central collisions of 250 A MeV Au + Au are presented. The results of this measurement and a model analysis are used to study the expansion and clustering of the hot and compressed transient state formed in central