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Title:

Probing the Equation of State of Superdense Neutron-Rich Matter with Terrestrial Nuclear Reactions

Speaker:

Prof. Bao-An Li

(Department of Physics and Astronomy, Texas A&M University-Commerce, USA)

Time and place:

12:30, August 13 (Monday), 2012, Lecture Hall/INPAC (上海交通大学粒子物理宇宙学研究所，包玉刚图书馆东楼四楼(从北门进))

Abstract

Neutron  stars are highly condensed stellar objects produced in supernova  explosions, the end point in the evolution of more massive stars. The  masses of neutron stars are approximately in the range of 1-2 times of  the sun, whereas their typical radii are only 10-20km. The matter they  contain, primarily neutrons, is therefore the densest found outside  black holes in the universe. Neutron stars thus provide a laboratory to  test our understanding of nature at the extreme, and verify our theories  of matter, energy and their interactions. However, neutron stars are  still among the most mysterious objects in the universe and they pose a  great scientific challenge. The structure and properties of neutron  stars are determined by the Equation of State (EOS which is a  relationship among pressure, density and temperature) of neutron-rich  nuclear matter. For the latter, what has been most uncertain is the  density dependence of nuclear symmetry energy related to the energy cost  of converting protons into neutrons in nuclear medium at various  densities.  Nuclear reactions conducted in terrestrial laboratories,  especially heavy-ion reactions induced by highly neutron-rich  radioactive beams, can produce nuclear matter similar to those contained  in neutron stars. In this talk, I will first review the latest progress  in constraining the EOS of neutron-rich nuclear matter especially the  density dependence of nuclear symmetry energy around and below the  saturation density of nuclear matter. I will then discuss a few open  questions regarding the symmetry energy at supra-saturation densities.  Finally, several ramifications of nuclear symmetry energy on properties  of neutron stars and gravitational waves will be discussed.