Observation of an ultralow- Q -value electron-capture channel decaying to As75 via a high-precision mass measurement

Observation of an ultralow-Q-value electron-capture channel decaying to 75As via a high-precision mass measurement

A precise determination of the atomic mass of 75As has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. The mass excess is measured to be −73035.519(42)keV/c2, which is a factor of 21 more precise and 1.3(9)keV/c2 lower than the adopted value in the newest Atomic Mass Evaluation (AME2020). This value has been used to determine the ground-state–to–ground-state electron-capture decay Q value of 75Se and β− decay Q value of 75Ge, which are derived to be 866.041(81) keV and 1178.561(65) keV, respectively. Using the nuclear energy-level data of 860.00(40) keV, 865.40(50) keV (final states of electron capture), and 1172.00(60) keV (final state of β− decay) for the exc…

Observation of an ultralow- Q -value electron-capture channel decaying to As 75 via a high-precision mass measurement