β decay as new probe for the low-energy E1 strength

In this contribution, it is evaluated whether high Q-value β decays from mothers with low ground-state spin are suitable to probe the structure of 1− levels associated with the pygmy dipole response. A comparison of data from the exemplary 136I →136Xe β decay and the 136Xe(γ,γ′) reaction reveals that some 1− levels are populated in both reactions but with a different pattern. An investigation within the microscopic quasiparticle phonon model shows that the pattern is related to the population of different parts of the wave functions of these 1− levels establishing β decay as a novel probe.