Experimental study of asymmetric nuclear matter EoS from heavy-ion reactions

Neutron star (NS) is believed to be created as a remnant of supernova explosion. The property of neutron star can be described with the thermodynamical character (Equation of State, EoS) of nuclear matter. For the determination of outer core NS-EoS, we have performed a series of measurements using heavy ion accelerator experimental facilities in Japan, such as RIKEN Radio Isotope Beam Factory (RIBF) and Heavy Ion Medical Accelerator in Chiba.

Especially for the heavy ion reaction experiment at RIBF, an international collaboration, named SPiRIT, to study the density dependence of symmetry energy term in nuclear EoS has been formed since 2009. One of the main devices of experimental setup is a Time Projection Chamber (TPC) which will be installed into the SAMURAI dipole magnet at RIBF. The TPC will measure charged pions, protons and light ions simultaneously in heavy RI collisions of neutron rich Sn reactions, Sn-132 + Sn-124, and neutron deficient Sn reactions, Sn-108 + Sn-112, at Ebeam=270MeV/u.

In this talk, after discussing the conceptual design of the SPiRIT project, recent result on nuclear symmetry energy give by SPiRIT will be given in addition to the status of data analysis for experiment at HIMAC.