The Smallest Known Q Value of Any Nuclear Decay: the Rare beta-minus Decay of 115In(9/2+) ->115Sn(3/2+)

The ground-state-to-ground-state Q-beta-minus value of 115In was determined to 497.68(17) keV using a high precision Penning trap facility at the University of Jyvaskyla, Finland. From this, a Q-beta-minus value of 0.35(17) keV is obtained for the rare beta-minus decay to the first excited state of 115Sn at 497.334(22) keV. The partial half-life was determined to 4.1(6)E20 yr using ultra low-background gamma-ray spectrometry in an underground laboratory. Theoretical modeling of this 2nd-forbidden unique beta-minus transition was also undertaken and resulted in Q-beta-minus = 57(+19-12)eV using the measured half-life. The discrepancy between theory and experiment could be attributed to atomic effects enhanced by the low Q value. The present study implies that this transition has the lowest Q value of any known nuclear beta decay.

WIESLANDER E.;  SUHONEN J.;  ERONEN T.;  HULT Mikael;  ELOMAA V.V.;  JOKINEN A.;  MARISSENS Gerd;  MISIASZEK M.;  MUSTONEN M.T.;  RAHAMAN S.;  WEBER C.;  AEYSTOE J.; 

2009-09-28

AMER PHYSICAL SOC

JRC51296

0031-9007,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC51296,   

10.1103/PhysRevLett.103.122501,