Fits to the transverse momentum distributions of charged particles produced in p - p collisions at LHC energies based on the Tsallis distribution have been shown to work over 14 orders of magnitude. T
The transverse momentum distributions of charged particles in p-Pb collisions as sqrt{s_{NN}} = 5.02 TeV measured by the ALICE collaboration are fitted using Tsallis statistics. The use of a thermodynamically consistent form of this distribution lead
s to an excellent description of the transverse momentum distributions for all rapidity intervals. The values of the Tsallis parameter q, the temperature T and the radius R of the system do not change within the measured pseudorapidity intervall.
An overview is presented of transverse momentum distributions of particles at the LHC using the Tsallis distribution. The use of a thermodynamically consistent form of this distribution leads to an excellent description of charged and identified part
icles. The values of the Tsallis parameter q are truly remarkably consistent.
The collision smearing of the nucleon momenta about their initial values during relativistic nucleus-nucleus collisions is investigated. To a certain degree, our model belongs to the transport type, and we investigate the evolution of the nucleon sys
tem created at a nucleus-nucleus collision. However, we parameterize this development by the number of collisions of every particle during evolution rather than by the time variable. It is assumed that the group of nucleons which leave the system after the same number of collisions can be joined in a particular statistical ensemble. The nucleon nonequilibrium distribution functions, which depend on a certain number of collisions of a nucleon before freeze-out, are derived.
THERMUS is a package of C++ classes and functions allowing statistical-thermal model analyses of particle production in relativistic heavy-ion collisions to be performed within the ROOT framework of analysis. Calculations are possible within three st
atistical ensembles; a grand-canonical treatment of the conserved charges $B$, $S$ and $Q$, a fully canonical treatment of the conserved charges, and a mixed-canonical ensemble combining a canonical treatment of strangeness with a grand-canonical treatment of baryon number and electric charge. THERMUS allows for the assignment of decay chains and detector efficiencies specific to each particle yield, which enables sensible fitting of model parameters to experimental data.
Recent results related to the chemical equilibration of hadrons in the final state of p-p and heavy ion collisions are reviewed.
One of the striking features of particle production at high beam energies is the near equal abundance of matter and antimatter in the central rapidity region. In this paper we study how this symmetry is reached as the beam energy is increased. In par
ticular, we quantify explicitly the energy dependence of the approach to matter/antimatter symmetry in proton-proton and in heavy-ion collisions. Expectations are presented also for the production of more complex forms of antimatter like antihypernuclei.
Prospects for strangeness production in pp collisions at the Large Hadron Collider (LHC) are discussed within the statistical model. Firstly, the system size and the energy dependence of the model parameters are extracted from existing data and extra
polated to LHC energy. Particular attention is paid to demonstrate that the chemical decoupling temperature is independent of the system size. In the energy regime investigated so far, strangeness production in pp interactions is strongly influenced by the canonical suppression effects. At LHC energies, this influence might be reduced. Particle ratios with particular sensitivity to canonical effects are indicated. Secondly, the relation between the strangeness production and the charged-particle multiplicity in pp interactions is investigated. In this context the multiplicity dependence studied at Tevatron is of particular interest. There, the trend in relative strangeness production known from centrality dependent heavy-ion collisions is not seen in multiplicity selected pp interactions. However, the conclusion from the Tevatron measurements is based on rather limited data samples with low statistics and number of observables. We argue, that there is an absolute need at LHC to measure strangeness production in events with different multiplicities to possibly disentangle relations and differences between particle production in pp and heavy-ion collisions.
A thermal-model analysis of particle production of p-p collisions at sqrt(s) = 17 GeV using the latest available data is presented. The sensitivity of model parameters on data selections and model assumptions is studied. The system-size dependence of
thermal parameters and recent differences in the statistical model analysis of p-p collisions at the super proton synchrotron (SPS) are discussed. It is shown that the temperature and strangeness undersaturation factor depend strongly on kaon yields which at present are still not well known experimentally. It is conclude, that within the presently available data at the SPS it is rather unlikely that the temperature in p-p collisions exceeds significantly that expected in central collisions of heavy ions at the same energy.
The statistical model assuming chemical equilibriumand local strangeness conservation describes most of the observed features of strange particle production from SIS up to RHIC. Deviations are found as the maximum in the measured K+/pi+ ratio is much
sharper than in the model calculations. At the incident energy of the maximum, the statistical model shows that freeze out changes regime from one being dominated by baryons at the lower energies toward one being dominated by mesons. It will be shown how deviations from the usual freeze-out curve influence the various particle ratios. Furthermore, other observables exhibit also changes just in this energy regime.
