The branching ratio of the sub-threshold 1$^{-}$ state in the $\beta$-decay of $^{16}$N

A measurement of the $\beta $-delayed $\alpha $ decay of $^{16}$N can give information about the E1 component of the astrophysical S-factor of the $^{12}$C($\alpha $,$\gamma )^{16}$O reaction. The uncertainty in this measurement depends on many parameters, which are used in the fitting procedure. One of them is the ratio of the $\beta $ decay in $^{16}$N, populating the sub-threshold 1$^{-}$ state in $^{16}$O. We have performed a new measurement of this branching ratio using Gammasphere. The $^{16}$N particles were produced by bombarding a deuterium target with a $^{15}$N beam from the ATLAS accelerator at Argonne. From this experiment a new branching ratio has been obtained, which is about 10{\%} higher than the previous value. The implication of this new value on the S(E1) factor will be discussed. \textit{This work was supported in part by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 and by the NSF Grant No. PHY-02-16783 (Joint Institute for Nuclear Astrophysics).}