Bulk observables at 5.02 TeV using quasiparticle anisotropic hydrodynamics

We compare predictions of 3+1D quasiparticle anisotropic hydrodynamics (aHydroQP) for a large set of bulk observables with experimental data collected in 5.02 TeV Pb–Pb collisions. We make predictions for identified hadron spectra, identified hadron average transverse momentum, charged particle multiplicity as a function of pseudorapidity, the kaon-to-pion ($$K/\pi $$ K / π ) and proton-to-pion ($$p/\pi $$ p / π ) ratios, identified particle and charged particle elliptic flow, and HBT radii. We compare to data collected by the ALICE collaboration in 5.02 TeV Pb–Pb collisions. We find that, based on available data, these bulk observables are well described by aHydroQP with an assumed initial central temperature of $$T_0=630$$ T 0 = 630 MeV at $$\tau _0 = 0.25$$ τ 0 = 0.25 fm/c and a constant specific shear viscosity of $$\eta /s=0.159$$ η / s = 0.159 , which corresponds to a peak specific bulk viscosity of $$\zeta /s = 0.048$$ ζ / s = 0.048 . In particular, we find that the momentum dependence of the kaon-to-pion ($$K/\pi $$ K / π ) and proton-to-pion ($$p/\pi $$ p / π ) ratios reported recently by the ALICE collaboration are extremely well described by aHydroQP in the 0–5% centrality class.

Spectral temperature of π− mesons in proton–carbon interactions at 4.2 GeV/c in the framework of UrQMD model

Transverse momentum [Formula: see text] spectra of [Formula: see text] mesons calculated using ultra-relativistic quantum molecular dynamic (UrQMD) model (Latest version 3.3-p2) simulations have been compared with [Formula: see text] spectra of [Formula: see text] mesons, obtained experimentally in interactions of protons beam with carbon nuclei (propane as target) at momentum of 4.2 GeV/c. Spectral temperatures of negative pions obtained in experimental and UrQMD model simulated interactions of protons beam with carbon nuclei have been calculated by fitting both spectra with four different fitting functions, i.e. Hagedorn thermodynamic, Boltzmann distribution, Gaussian and exponential functions. These functions are used commonly for describing hadron spectra and their spectral temperatures. Hagedorn thermodynamic function has been recommended as the most suitable function to extract the temperature of negative pions at above momentum among these four functions.

Data structure in the HIJING 2.0 Monte Carlo program

The Heavy-Ion Jet Interaction Generator (HIJING) Monte Carlo model was developed to simulate hadron production in proton–proton, proton–nucleus and nucleus–nucleus collisions. It has been updated recently with the latest parton distributions functions (PDFs) and new set of the parameters in the two-component mini-jet model that controls total [Formula: see text] cross-section and the central pseudorapidity density. We will discuss these new elements in the HIJING 2.0 model, derive the two-component model from the eikonal formalism of hadron–hadron collisions and review the hadron spectra and multiplicity distributions as compared to recent experimental data at the LHC energies. We will review in particular the data structure of the Monte Carlo program and discuss future improvements.