A 50 cm3 Ge(Li) detector has been used to re-examine the reaction 9Be(τ, γγ)12C over a previously reported resonance at E(τ) = 1.739±0.007 MeV which was suggested as the lowest T = 2 state in 12C. This state is expected to γ-decay via the 1+, T = 1 state at 15.11 MeV. However a search with τ bombarding energies ranging two standard deviations above and below the reported resonance energy revealed no resonance in high-energy γ-rays. An upper limit of ΓτΓγ/Γ < 2.0 meV is established for the T = 2 resonance strength which is one-fourth of the previously reported strength and which strongly corroborates an additional negative result reported as ΓτΓγ/Γ < 1.5 meV. In the course of the experiment a new value of Γlab = 2.94±0.20 keV was obtained for the resonance at Ep = 1.083 MeV in 9Be(p, γ)10B.
- Nuclear reactions
ASJC Scopus subject areas
- Nuclear and High Energy Physics