Using [beta]-decay to map the E2 strength in the Cd isotopes and the downfall of vibrational motion

Abstract

The β decay of ¹¹²Ag has been used to populate spin 0⁺ and 2⁺ states in ¹¹²Cd to 3 MeV excitation energy. The statistical quality obtained allows the extraction of very weak γ-ray branching ratios that, combined with known level lifetimes, enables the determination of the B(E2) values or upper limits for transitions populating the proposed two-phonon states. While candidates for 3⁺, 4⁺, and 6⁺ three-phonon levels have been identified, there are no candidates for the 0⁺ and 2⁺ three phonon levels, and the upper limits of the B(E2) values indicate that phonon E2 strength is not fragmented, but absent below 5ℏw_2.