Links Between Heavy Ion and Astrophysics

Heavy ion experiments provide important data to test astrophysical models. The high density equation of state can be probed in HI collisions and applied to the hot protoneutron star formed in core collapse supernovae. The Parity Radius Experiment (PREX) aims to accurately measure the neutron radius of $^{208}$Pb with parity violating electron scattering. This determines the pressure of neutron rich matter and the density dependence of the symmetry energy. Competition between nuclear attraction and coulomb repulsion can form exotic shapes called nuclear pasta in neutron star crusts and supernovae. This competition can be probed with multifragmentation HI reactions. We use large scale semiclassical simulations to study nonuniform neutron rich matter in supernovae. We find that the coulomb interactions in astrophysical systems suppress density fluctuations. As a result, there is no first order liquid vapor phase transition. Finally, the virial expansion for low density matter shows that the nuclear vapor phase is complex with significant concentrations of alpha particles and other light nuclei in addition to free nucleons.Comment: 8 pages, 6 figures. To be published in "Dynamics and Thermodynamics with Nucleon Degrees of Freedom", eds. P. Chomaz, F. Gulminelli, J. Natowitz, and S. Yennello, http://cyclotron.tamu.edu/wci3/wci_book.htm

Parity Violation in Astrophysics

Core collapse supernovae are gigantic explosions of massive stars that radiate 99% of their energy in neutrinos. This provides a unique opportunity for large scale parity or charge conjugation violation. Parity violation in a strong magnetic field could lead to an asymmetry in the neutrino radiation and recoil of the newly formed neutron star. Charge conjugation violation in the neutrino-nucleon interaction reduces the ratio of neutrons to protons in the neutrino driven wind above the neutron star. This is a problem for r-process nucleosynthesis in this wind. On earth, parity violation is an excellent probe of neutrons because the weak charge of a neutron is much larger than that of a proton. The Parity Radius Experiment (PREX) at Jefferson Laboratory aims to precisely measure the neutron radius of $^{208}$Pb with parity violating elastic electron scattering. This has many implications for astrophysics, including the structure of neutron stars, and for atomic parity nonconservation experiments.}Comment: 4 pages, 2 figures, proceedings of PAVI04 conference in Grenoble, Franc

Weakness or Strength in the Golden Years of RHIC and LHC?

Recent LHC data suggest that perturbative QCD provides a qualitatively consistent picture of jet quenching. Constrained to RHIC pi0 suppression, zero parameter WHDG energy loss predictions agree quantitatively with the charged hadron v2 and D meson RAA measured at LHC and qualitatively with the charged hadron RAA. On the other hand, RHIC-constrained LHC predictions from fully strongly-coupled AdS/CFT qualitatively oversuppress D mesons compared to data; light meson predictions are on less firm theoretical ground but also suggest oversuppression. More detailed data from heavy, especially B, mesons will continue to help clarify our picture of the physics of the quark-gluon plasma. Since the approach of pQCD predictions to LHC data occurs at momenta >~ 15 GeV/c, a robust consistency check between pQCD and both RHIC and LHC data requires RHIC jet measurements.Comment: 4 pages. 3 figures. Proceedings for Hard Probes 2012. Minor grammatical and reference changes from v

Multi-messenger observations of neutron rich matter

Neutron rich matter is central to many fundamental questions in nuclear physics and astrophysics. Moreover, this material is being studied with an extraordinary variety of new tools such as the Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that uses parity violating electron scattering to measure the neutron radius in $^{208}$Pb. This has important implications for neutron stars and their crusts. We discuss X-ray observations of neutron star radii. These also have important implications for neutron rich matter. Gravitational waves (GW) open a new window on neutron rich matter. They come from sources such as neutron star mergers, rotating neutron star mountains, and collective r-mode oscillations. Using large scale molecular dynamics simulations, we find neutron star crust to be very strong. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. Finally, neutrinos from core collapse supernovae (SN) provide another, qualitatively different probe of neutron rich matter. Neutrinos escape from the surface of last scattering known as the neutrino-sphere. This is a low density warm gas of neutron rich matter. Observations of neutrinos can probe nucleosyntheses in SN. Simulations of SN depend on the equation of state (EOS) of neutron rich matter. We discuss a new EOS based on virial and relativistic mean field calculations. We believe that combing astronomical observations using photos, GW, and neutrinos, with laboratory experiments on nuclei, heavy ion collisions, and radioactive beams will fundamentally advance our knowledge of compact objects in the heavens, the dense phases of QCD, the origin of the elements, and of neutron rich matter.Comment: 13 pages, 4 figures, Added discussion of dipole polarizability, pygmy resonances, and neutron skin

Dissociation and pain perception : an experimental investigation

textDissociative symptoms and abnormalities in pain perception have been associated with a range of disorders. We tested whether experimentally induced increases in state dissociation would cause an analgesic response, and whether this effect would be moderated by participants' history of trauma and dissociative experiences. Participants (n=120) were classified based on their histories of traumatic and dissociative experiences: No trauma or dissociation (NN), trauma without dissociation (TN), or trauma with dissociation (TD). All participants were randomized to a dissociation induction condition via audiophotic stimulation or a credible control condition and were compared on prepost changes in subjective pain and pain tolerance in response to a standard cold-pressor test. Unexpectedly, dissociation induction did not lead to greater pain tolerance or reduced self-reported pain. However, increases in state dissociation significantly predicted increased immersion time and decreased subjective pain.Psycholog