Gamma decay of the first two {ce:inline-formula}T = 3/2{/ce:inline-formula} states of 15N

Abstract Gamma transitions from the first two {ce:inline-formula}T = 3/2{/ce:inline-formula} states of 15 N have been studied via the reaction 14 C(p,γ) 15 N. The angular distributions of the three transitions from the lowest {ce:inline-formula}T = 3/2{/ce:inline-formula} state at {ce:inline-formula}E x = 11.61MeV{/ce:inline-formula} are isotropic, in agreement with the {ce:inline-formula}J π = 1/2 + {/ce:inline-formula} assignment for the state. For the second {ce:inline-formula}T = 3/2{/ce:inline-formula} state at {ce:inline-formula}E x = 12.52MeV{/ce:inline-formula} the angular distributions are in agreement with {ce:inline-formula}J π = 5/2 + {/ce:inline-formula}. The transitions {ce:inline-formula}12.52 → 5.27{/ce:inline-formula} and {ce:inline-formula}12.52 → 6.33MeV{/ce:inline-formula} are essentially pure Ml and pure E1, respectively. A comparison of the strength of the allowed {ce:inline-formula}β − {/ce:inline-formula} decay of the 15 C ground state (the supposed parent analogue state of the 11.61 MeV state of 15 N) to the 5.30 MeV state of 15 N with the strength of the {ce:inline-formula}11.61 → 5.30MeV{/ce:inline-formula} γ-transition in 15 N suggests a considerable contribution from the orbital part in the M1 matrix element. The Zuker-Buck-McGrory shell-model wave functions for 15 N give a qualitative description of the observed γ-decay. But the disagreement in decay strengths between theory and experiment and the omission of the known 1p{ce:inline-formula} 3/2{/ce:inline-formula} hole state (6.33 MeV) suggest the need of 12 C core excitation in the ZBM calculation.