Prospect of heavy-ion collision experiments at J-PARC

Abstract

In order to explore phase structures in high-baryon density regime of the QCD phase diagram and study dense quark/hadronic matter which may exist in the core of neutron stars, we proposed a heavy-ion program at J-PARC (J-PARC-HI). In heavy-ion collisions at J-PARC (1-19 AGeV/c), the maximum baryon density reaches 5-10 times the normal nuclear density. We designed heavy-ion acceleration scheme at J-PARC. A heavy-ion beam will be produced in a new heavy-ion injector (a linac and a booster ring) and accelerated in the existing 3-GeV and 50-GeV synchrotrons (Rapid-Cycling Synchrotron and Main Ring). One of the world’s highest intensity proton accelerator complex J-PARC, is expected to produce the world’s highest heavy-ion beams (up to U) of $10^{11}$ Hz, which provides extremely high rate heavy-ion collisions to measure rare observables in high statistics. We aim at measuring dileptons (di-electrons and di-muons), photons, higher-order fluctuations of conserved charges, (higher-order) collective flow to explore phase structures, and multi-strangeness hadrons and nuclei, and two-particle correlations for physics related to neutron stars. We designed a multi-purpose large acceptance Toroidal magnet spectrometer for lepton, photon, and hadron measurements. We also designed a spectrometer which measures hadrons and nuclei only around beam rapidity region to search for various hypernuclei and strangelets. The latter spectrometer could accept the full beam intensity of J-PARC. In this talk, physics goals, experimental design of the spectrometers, and expected physics results will be discussed.