Determination of theQECvalues of theT=1/2mirror nucleiNa

Abstract

We report the first direct measurement of the transition energy QEC of the 21 Na mixed FermiGamow-Teller decay. This is the first of the T = 1/2 mirror nuclei decays used for the determination of V ud to be measured with Penning trap mass spectrometry. In addition, the 29 P mass was measured directly for the first time and used along with the mass of its daughter, 29 Si, for the independent QEC determination of this decay. The obtained QEC 21 Na = 3547.11(9) keV and ME 29 P = −16953.15(47) keV significantly improve the latest published values and reduce the contribution of the QEC uncertainty on Ft mirror to the same order as the theoretical corrections.

High-precision half-life determination for Na21 using a 4π gas-proportional counter

“…Combined with world-averaged results for the 21 Na Q EC value and branching ratio [20], this world-average 21 Na halflife of T 1/2 = 22.448(8) s yields an Ft mirror value of:…”

“…Fractional uncertainties in the Ft mirror value for 21 Na based on the Q EC value, branching ratio (BR), and half-life from Refs. [20] and [6], the theoretical corrections from Ref. [4], and the half-life value reported here.…”

QEC -value determination for Na21→Ne21 and Karthein1, Atanasov2, Blaum3 et al. 2019Phys. Rev. C

“…When the proposal for the experiments reported here was submitted to the ISOLDE and Neutron Time-of-Flight Committee (INTC) at CERN [16] the Q EC value of both isotopes were the second-largest fractional contribution to their Ft values. New measurements were reported since by TITAN [17] and LEBIT [18]. The data presented in this work constitutes the most precise results for the Q EC values of these two isotopes to date.…”

Precise determination of theCd113fourth-forbidden non-uniqueβ-decayQvalue

“…In this way, magnetic field fluctuations can be eliminated to first order. The effect of non-linear magnetic field fluctuations on the cyclotron frequency ratio was previously studied at LEBIT [43] and found to contribute at the level of 1.2(6) × 10 −10 per hour. Since the time taken to obtain a resonance was slightly less than one hour, this effect is negligible at the level of precision achieved in this work.…”