Statistical hadronisation phenomenology

The analyses of hadron production in the framework of the statistical hadronisation model are reviewed. The analysis of average multiplicities in collisions at relatively low centre-of-mass energy confirms previous findings, namely the universality of hadronisation temperature and of strange to non-strange quark production rate. The study of transverse momentum spectra of identified hadrons allows a further determination of the hadronisation temperature which is found to be compatible with that obtained from fits to average multiplicities.Comment: 5 pages, 4 .eps figures, talk given at Statistical QCD, Bielefeld, August 2001, to appear in the proceeding

Thermodynamic equilibrium with acceleration and the Unruh effect

We address the problem of thermodynamic equilibrium with constant acceleration along the velocity field lines in a quantum relativistic statistical mechanics framework. We show that for a free scalar quantum field, after vacuum subtraction, all mean values vanish when the local temperature T is as low as the Unruh temperature T_U = A/2\pi where A is the magnitude of the acceleration four-vector. We argue that the Unruh temperature is an absolute lower bound for the temperature of any accelerated fluid at global thermodynamic equilibrium. We discuss the conditions of this bound to be applicable in a local thermodynamic equilibrium situation.Comment: 15 pages, 2 figures; updated version accepted for publication in Phys. Rev.

Polarization and Chirality: the quantum features of the Quark Gluon Plasma

Polarization and chirality are direct manifestations of quantum mechanics in the Quark Gluon Plasma as a relativistic fluid. This is one of the reasons why they are intriguing phenomena, that have attracted so much attention lately. In this talk I will review what is, in my view, the current theoretical understanding and highlight the most interesting recent result.Comment: 7 pages, plenary talk given at the conference Quark Matter 2018. arXiv admin note: text overlap with arXiv:1711.0878

Polarization in relativistic heavy ion collisions: a theoretical perspective

We review the theoretical framework for the calculation of particle polarization in relativistic heavy ion collisions within the hydrodynamical model. The covariant decomposition of the mean spin vector is presented and open theoretical issues addressed.Comment: 6 pages, talk given at Strangeness in Quark Matter conference, Utrecht, July 10-15 201

A Monte-Carlo generator for statistical hadronization in high energy e+e- collisions

We present a Monte-Carlo implementation of the Statistical Hadronization Model in e+e- collisions. The physical scheme is based on the statistical hadronization of massive clusters produced by the event generator Herwig within the microcanonical ensemble. We present a preliminary comparison of several observables with measurements in e+e- collisions at the Z peak. Although a fine tuning of the model parameters is not carried out, a general good agreement between its predictions and data is found.Comment: 19 pages, 28 figures, 6 tables. v2: added sections on comparison between the Statistical Hadronization Model and the Cluster Model and on the interplay between Herwig cluster splitting algorithm and Statistical Hadronization Model predictions. Fixed typos and references added. Version accepted for publication in EPJ