Search for tri-nucleon decays of 76 Ge in GERDA.
M AgostiniA AlexanderG AraujoA M BakalyarovM BalataI BarabanovL BaudisC BauerS BelogurovA BettiniL BezrukovV BiancacciE BossioV BotheR BrugneraA CaldwellS CalgaroC CattadoriA ChernogorovP-J ChiuT ComellatoV D'AndreaE V DemidovaA Di GiacintoN Di MarcoE DoroshkevichF FischerM FominaA GangapshevA GarfagniniC GoochP GrabmayrV GurentsovK GusevJ HakenmüllerS HemmerW HofmannM HultL V InzhechikJ Janicskó CsáthyJ JochumM JunkerV KazalovY KermaïdicH KhushbakhtT KihmK KilgusI V KirpichnikovA KlimenkoK T KnöpfleO KochetovV N KornoukhovP KrauseV V KuzminovM LaubensteinM LindnerI LippiA LubashevskiyB LubsandorzhievG LutterC MacolinoB MajorovitsW ManeschgL ManzanillasG MarshallM MisiaszekM MorellaY MüllerI NemchenokM NeubergerL PandolaK PelczarL PertoldiP PiseriA PulliaL RauscherM RedchukS RiboldiN RumyantsevaC SadaS SailerF SalamidaS SchönertJ SchreinerM SchüttA-K SchützO SchulzM SchwarzB SchwingenheuerO SelivanenkoE ShevchikM ShirchenkoL ShtembariH SimgenA SmolnikovD StukovS SullivanA A VasenkoA VeresnikovaC VignoliK von SturmT WesterC WiesingerM WojcikE YanovichB ZatschlerI ZhitnikovS V ZhukovD ZinatulinaA ZschockeA J ZsigmondK ZuberG Zuzelnull nullPublished in: The European physical journal. C, Particles and fields (2023)
We search for tri-nucleon decays of 76 Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to 73 Cu, 73 Zn, and 73 Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of 73 Ga to 73 Ge (stable). We search for the 73 Ga decay exploiting the fact that it dominantly populates the 66.7 keV 73 m Ga state with half-life of 0.5 s. The nnn-decays of 76 Ge that proceed via 73 m Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2 × 10 26 yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.