Precise branching ratios to unbound 12C states from 12N and 12B β-decays

Abstract

Two complementary experimental techniques have been used to extract precise branching ratios to unbound states in 12 C from 12 N and 12 B β-decays. In the first the three α-particles emitted after βdecay are measured in coincidence in separate detectors, while in the second method 12 N and 12 B are implanted in a detector and the summed energy of the three α-particles is measured directly. For the narrow states at 7.654 MeV (0 +) and 12.71 MeV (1 +) the resulting branching ratios are both smaller than previous measurements by a factor of 2. The experimental results are compared to no-core shell model calculations with realistic interactions from chiral perturbation theory, and inclusion of three-nucleon forces is found to give improved agreement.

R-matrix analysis of theβdecays ofN12Hyldegaard1, Alcorta2, Bastin3 et al. 2010Phys. Rev. CSelf Cite627410View full textAdd to dashboardCite

“…corrected for. Note, however, that the areas under the two peaks are consistent with each other [15].…”

“…Detailed explanations are published elsewhere. The first experiment utilized the IGISOL facility at the Jyväskylä Accelerator Laboratory (JYFL), Jyväskylä, Finland [15][16][17][18]. The experimental details for these measurements are given in Refs.…”

“…The experimental details for these measurements are given in Refs. [15][16][17]. Beams of 12 N and 12 B were produced, accelerated to about 25 keV, and mass separated using the ISOL method before reaching the experimental setup.…”

“…(See Refs. [15] and [19] for details). High-energy beams of 12 N and 12 B were produced and separated in the TriµP separator, after which they were defocused and implanted in a very finely segmented detector.…”

“…In Ref. [15] β-decay branching ratios are extracted, and, for narrow states, Gamow-Teller matrix elements deduced and compared to theory. More experimental details on this analysis for the ISOL experiment are given in Ref.…”