Author:
Guinn I.S.,Arnquist I.J.,Avignone F.T.,Barabash A.S.,Barton C. J.,Bertrand F.E.,Bos B.,Busch M.,Buuck M.,Caldwell T.S.,Chan Y-D.,Christofferson C.D.,Chu P-H.,Clark M.L.,Cuesta C.,Detwiler J.A.,Drobizhev A.,Edwins D. W.,Efremenko Yu.,Ejiri H.,Elliott S.R.,Gilliss T.,Giovanetti G.K.,Green M.P.,Gruszko J.,Guiseppe V.E.,Haufe C.R.,Hegedus R.J.,Henning R.,Hervas Aguilar D.,Hoppe E.W.,Hostiuc A.,Kidd M.F.,Kim I.,Kouzes R.T.,Lopez A.M.,López-Castaño J.M.,Martin E. L.,Martin R.D.,Massarczyk R.,Meijer S.J.,Mertens S.,Myslik J.,Oli T.K.,Othman G.,Pettus W.,Poon A.W.P.,Radford D.C.,Rager J.,Reine A.L.,Rielage K.,Ruof N.W.,Stortini M.J.,Tedeschi D.,Varner R.L.,Wilkerson J.F.,Wiseman C.,Xu W.,Yu C.-H.,Zhu B.X.
Abstract
Abstract
The MAJORANA DEMONSTRATOR is searching for double-beta decay of 76Ge to excited states (E.S.) in 76Se using a modular array of high purity Germanium detectors. 76Ge can decay into three E.S.s of 76Se. The E.S. decays have a clear event signature consisting of a ββ-decay with the prompt emission of one or two γ-rays, resulting in with high probability in a multi-site event. The granularity of the DEMONSTRATOR detector array enables powerful discrimination of this event signature from backgrounds. Using 21.3 kg-y of isotopic exposure, the DEMONSTRATOR has set world leading limits for each E.S. decay, with 90% CL lower half-life limits in the range of (0.56 ‒ 2.1) ⋅ 1024 y. In particular, for the 2v transition to the first 0+ E.S. of 76Se, a lower half-life limit of 0.68 ⋅ 1024 at 90% CL was achieved.
Subject
General Physics and Astronomy