Pseudorapidity distributions of charged particles as a function of mid- and forward rapidity multiplicities in pp collisions at $$\sqrt{s}$$ = 5.02, 7 and 13 TeV

The multiplicity dependence of the pseudorapidity density of charged particles in proton–proton (pp) collisions at centre-of-mass energies $$\sqrt{s}~=~5.02$$ s = 5.02 , 7 and 13 TeV measured by ALICE is reported. The analysis relies on track segments measured in the midrapidity range ($$|\eta | < 1.5$$ | η | < 1.5 ). Results are presented for inelastic events having at least one charged particle produced in the pseudorapidity interval $$|\eta |<1$$ | η | < 1 . The multiplicity dependence of the pseudorapidity density of charged particles is measured with mid- and forward rapidity multiplicity estimators, the latter being less affected by autocorrelations. A detailed comparison with predictions from the PYTHIA 8 and EPOS LHC event generators is also presented. The results can be used to constrain models for particle production as a function of multiplicity in pp collisions.

Pseudorapidity distributions of fast target protons in 32S-Em collisions at Dubna energy

In this paper, the possible mechanisms, which are responsible for the production of fast target fragments (gray particles with energy 26 up to 400[Formula: see text]MeV) that were emitted from the interactions of [Formula: see text]S nucleus with emulsion nuclei at energy 3.7[Formula: see text]A[Formula: see text]GeV, are studied by the pseudorapidity distribution. The angular distribution of the fast protons ([Formula: see text]-particles) emitted in the interactions of [Formula: see text]S-Em at 3.7[Formula: see text]A[Formula: see text]GeV is nicely described by exp (0.96 cos [Formula: see text], which was observed in proton-induced interactions up to incident energies of 800[Formula: see text]GeV. The pseudorapidity distributions of the produced [Formula: see text]-particles were investigated in order to study the characteristics of the emitted system of [Formula: see text]-particles for different target sizes (CNO, Em and AgBr groups of events). In all cases, the pseudorapidity distributions were parametrized using Gaussian fits. The temperature of the system emitting [Formula: see text]-particles (hot system) is predicated in the light of the proposed statistical model to be [Formula: see text][Formula: see text]MeV.

Observation of Gaussian Pseudorapidity Distributions for Produced Particles in Proton-Nucleus Collisions at Tevatron Energies

The statistical event-by-event analysis of inelastic interactions of protons in emulsion at 800 GeV reveals the existence of group of events with Gaussian pseudorapidity distributions for produced particles, as suggested by hydrodynamic-tube model. Events belong to very central collisions of protons with heavy emulsion nuclei with probability of realization of less than 1% and with multiplicity of shower particles exceeding (2-3 times) the average multiplicity in proton-nucleus collisions in emulsion. Bjorken’s energy density for these events reaches 2.0 GeV per fm3. The data are interpreted as a result of the QCD phase transition in proton-tube collisions at Tevatron energies.

Diffusion-model analysis of pPb and PbPb collisions at LHC energies

We present an analysis of centrality-dependent pseudorapidity distributions of produced charged hadrons in pPb and PbPb collisions at the Large Hadron Collider (LHC) energy of [Formula: see text] = 5.02 TeV, and of minimum-bias pPb collisions at 8.16 TeV within the non-equilibrium-statistical relativistic diffusion model (RDM). In a three-source approach, the role of the fragmentation sources is emphasized. Together with the Jacobian transformation from rapidity to pseudorapidity and the limiting fragmentation conjecture, these are essential for modeling the centrality dependence. For central PbPb collisions, a prediction at the projected FCC energy of [Formula: see text] = 39 TeV is made.

A Description of Pseudorapidity Distributions of Charged Particles Produced in Au+Au Collisions at RHIC Energies

In heavy ion collisions, charged particles come from two parts: the hot and dense matter and the leading particles. In this paper, the hot and dense matter is assumed to expand according to the hydrodynamic model including phase transition and decouples into particles via the prescription of Cooper-Frye. The leading particles are as usual supposed to have Gaussian rapidity distributions with the number equaling that of participants. The investigations of this paper show that, unlike low energy situations, the leading particles are essential in describing the pseudorapidity distributions of charged particles produced in high energy heavy ion collisions. This might be due to the different transparencies of nuclei at different energies.