Measurements of Gamow-Teller strength distributions via (t,$^{3}$He) and ($^{3}$He,t) reactions.

The (t,$^{3}$He) and ($^{3}$He,t) reactions at beam energies exceeding 100 MeV/nucleon are important tools to study the spin-isospin response of nuclei. Of particular interest is the extraction of Gamow-Teller strengths (B(GT)), since these provide direct information about weak-interaction rates that serve as input for stellar evolution calculations. Accurate measurements provide a way to test shell-model codes that can then be used to make estimates for stellar conditions that cannot be achieved in the laboratory. The combined capability to perform high-resolution ($^{3}$He,t) and (t,$^{3}$He) experiments (at RCNP, Osaka and the NSCL, respectively) makes these probes especially suited to perform such studies. The linear relationship between cross section and B(GT) has to be validated experimentally. ($^{3}$He,t) and (t,$^{3}$He)$^{ }$data on a variety of targets will be presented that is used to test the method, focusing on results from $^{26}$Mg($^{3}$He,t) and $^{26}$Mg(t,$^{3}$He) for which Gamow-Teller strengths have extracted over large excitation-energy ranges.