Transition probabilities in P and S; A Test for isospin symmetry

Tonev, D.*; De Angelis, G.*; Deloncle, I.*; Orlandi, R.  ; 27 of others*

The mirror nuclei P and S, produced via the Ne+C reaction at 33 MeV, were studied at Legnaro Laboratory using the EUCLIDES Si array coupled with the GASP Ge array. The observed B(E1) strengths of mirror E1 transitions, provide strong evidence for breaking of isospin symmetry in the A=31 mass region. The new finding are supported and explained by state-of-the-art beyond-mean-field calculations including 2- and 3-body forces. According to these findings, the breaking of isospin symmetry originate from violation of charge symmetry in the 2- and 3-body parts of the Coulomb potential.