%0 Journal Article
%T Precise measurement of branching ratios in the beta decay of 38Ca
%A H. I. Park
%A J. C. Hardy
%A V. E. Iacob
%A M. Bencomo
%A L. Chen
%A V. Horvat
%A N. Nica
%A B. T. Roeder
%A E. McCleskey
%A R. E. Tribble
%A I. S. Towner
%J Physics
%D 2015
%I arXiv
%X We present the full description of a measurement of the branching ratios for the beta-decay of 38Ca. This decay includes five allowed 0+ --> 1+ branches and a superallowed 0+ --> 0+ one. With our new result for the latter, we determine its ft value to be 3062.3(68) s, a result whose precision (0.2%) is comparable to the precision of the thirteen well known 0+ --> 0+ transitions used up till now for the determination of Vud, the up-down quark-mixing element of the CKM matrix. The 38Ca superallowed transition thus becomes the first addition to this set of transitions in nearly a decade and the first for which a precise mirror comparison is possible, thus enabling an improved test of the isospin-symmetry-breaking corrections required for the extraction of Vud.
%U http://arxiv.org/abs/1503.01367v1