Radiative lifetime and energy of the lowenergy isomeric level in ^{229}Th
Abstract
We estimate the range of the radiative lifetime and energy of the anomalous, lowenergy 3 /2^{+}(7.8 ±0.5 eV) state in the ^{229}Th nucleus. Our phenomenological calculations are based on the available experimental data for the intensities of M 1 and E 2 transitions between excited levels of the ^{229}Th nucleus in the K^{π}[N n_{Z}Λ ] =5 /2^{+}[633 ] and 3 /2^{+}[631 ] rotational bands. We also discuss the influence of certain branching coefficients, which affect the currently accepted measured energy of the isomeric state. From this work, we establish a favored region, 0.66 ×10^{6}seV^{3}/ω^{3}≤τ ≤2.2 ×10^{6}seV^{3}/ω^{3} , where the transition lifetime τ as a function of transition energy ω should lie at roughly the 95% confidence level. Together with the result of Beck et al. [LLNLPROC415170 (2009)], we establish a favored area where transition lifetime and energy should lie at roughly the 90% confidence level. We also suggest new nuclear physics measurements, which would significantly reduce the ambiguity in the present data.
 Publication:

Physical Review C
 Pub Date:
 November 2015
 DOI:
 10.1103/PhysRevC.92.054324
 arXiv:
 arXiv:1509.09101
 Bibcode:
 2015PhRvC..92e4324T
 Keywords:

 23.20.Lv;
 21.10.Tg;
 23.35.+g;
 27.90.+b;
 gamma transitions and level energies;
 Lifetimes;
 Isomer decay;
 220<
 =A;
 Physics  Atomic Physics;
 Nuclear Theory
 EPrint:
 12 pages, 5 figures