Measurement of the β-ν correlation coefficient aβν in the β decay of trapped 6He+ ions

We have measured the beta-nu angular correlation in the beta decay of He-6(+) ions using a transparent Paul trap. The He-6(+) ions, produced at GANIL, were first cooled and bunched before being injected in the LPCTrap setup. The angular correlation was inferred from the time of flight of recoil nuclei detected in coincidence with the beta particles. The detection system gives access to the full beta decay kinematics, providing means to check the data reliability and to reject a large fraction of background. We find a(beta nu) = -0.3335(73)(stat)(75)(syst), in agreement with the standard model prediction for a pure Gamow-Teller transition.