Soft physics results from the PHENIX experiment
Progress of Theoretical and Experimental Physics
High-energy heavy-ion collisions at RHIC-BNL and LHC-CERN provide a unique opportunity to study the properties of the high-temperature and high-density nuclear matter called the quark-gluon plasma (QGP), which is supposed to exist in the early universe or inside neutron stars. The PHENIX experiment is one of the major experiments at RHIC to study the properties of QGP, especially focusing on various particle identification capabilities including photons, leptons, and hadrons. This article
... This article summarizes the soft physics results from the PHENIX experiment, such as (1) global properties like transverse energy and multiplicity measurements as well as centrality determination, (2) transverse momentum distribution and the nuclear modification factor, which represents the modification of the spectra in A + A collisions relative to the binarycollision-scaled superposition of p+p data, (3) space-time properties with Hanbury Brown and Twiss (HBT) interferometry correlation measurement and source imaging, (4) elliptic collective expansion and higher-order harmonic event anisotropy, and (5) di-hadron correlation, jet modification, and medium response known as jet-quenching from the partonic energy loss and redistribution of the lost energy. These results are reviewed and discussed. Transverse energy, multiplicity measurement, and centrality High-energy heavy-ion collisions are characterized by the centrality that is given by the impact parameter, which is the nearest distance between two colliding nuclei perpendicular to the beam direction. In order to quantify the centrality, which controls the geometrical shape and volume of † Many thanks to the PHENIX Collaboration.