### Session T2: The Link between Neutrinos and the Origin of the Elements

 Monday, April 18, 2005 1:30PM - 2:06PM T2.00001: Overview: Neutrinos and Nucleosynthesis Invited Speaker: Baha Balantekin The astrophysical site of the r-process nucleosynthesis is not yet identified, but the neutrino-driven wind in a core-collapse supernova is one of the leading candidates. Neutrino interactions play a crucial role in such supernovae. Neutrino fluxes control the neutron-to-proton ratio in the high-entropy hot bubble which is where r-process nucleosynthesis is thought to take place. In this talk our current understanding of the role of neutrinos in core-collapse supernovae and the associated r-process nucleosynthesis will be reviewed. This work was supported in part by the U.S. National Science Foundation Grant No. PHY-0244384 and in part by the University of Wisconsin Research Committee with funds granted by the Wisconsin Alumni Research Foundation. Monday, April 18, 2005 2:06PM - 2:42PM T2.00002: Recent progress in neutrino - astrophysics connections Invited Speaker: James Kneller Of all the constituents within the standard model of particle physics our understanding of the neutrino has benefited the most from the interaction of astrophysics and terraphysics.' Much has been learned about the properties of the neutrino from each: experiments here on Earth temper our appreciation of the role that neutrinos play in the cosmos while astrophysics can provide the densities and temperatures in which the neutrinos do more than simply flee. But the reluctance of neutrinos to interact means that it is not until we venture into the most extreme environments of astrophysics that we observe neutrinos pushing back' as hard as they are being pushed'. We review two sites where this occurs: the early Universe and the accretion disk engines' of gamma ray bursts. Neutrinos play an important role in the evolution of the early Universe with a particular focus upon the electron neutrino in determining the primordial elemental composition via its participation in the most important reaction at that time. Within gamma ray burst accretion disks we again see the electron neutrinos at work in the nuclear reactions and through their function as the `coolant' for the disk. Removal of the disk energy, and its deposition into the remnants of the massive star surrounding the disk, may lead to the formation of highly relativistic jets that will later be observed as the burst. We show what has been learned so far about the neutrino and its properties from the study of such environments. Monday, April 18, 2005 2:42PM - 3:18PM T2.00003: Nucleosynthesis in Gamma Ray Bursts Invited Speaker: Rebecca Surman Recent developments in the understanding of the astrophysical site of gamma-ray bursts have opened up an exciting new area of nucleosynthesis research. Within the gamma-ray burst environment, nucleosynthesis can occur as explosive burning, in the jet, or in the outflow from the accretion disk. Here we consider the latter, focusing on the prospects that gamma-ray bursts may be responsible for the galactic production of certain rare nuclear species, such as $r$-process nuclei and light proton-rich nuclei.