Birds and the B(GT)s: Gamow-Teller Strengths from (t,3He) Charge Exchange Measurements

In pre-collapse and post-bounce stars, electrons excite Gamow-Teller (GT) resonances. Our current understanding of supernova explosion dynamics is guided by models that use data and calculations of GT strength (B(GT)) distributions for many nuclei. While measuring B(GT) for all nuclei is an unreasonable chore, limited charge exchange data can 1) reduce uncertainties for important nuclei and 2) vet assumptions/calculations used in different isotopic regions. (T,3He) experiments run at the National Superconducting Cyclotron Laboratory (NSCL) use a 450 MeV secondary triton beam to measure strengths with a resolution of about 150 keV from dispersion matching. Preliminary results from a recent experiment on 24Mg, 63Cu and 94Mo targets are discussed. This work is supported by JINA and the NSF (PHY 0214783, 0110253, 0140255).