Decay of “stretched” M4 resonance in 13C – first experimental studies at CCB IFJ PAN
Dr inż. Natalia Cieplicka-Oryńczak, IFJ PAN
“Stretched” states are one of the simplest nuclear excitations in the continuum. Their structure is dominated by a single particle-hole component for which both the excited particle and the residual hole occupy orbitals with the highest angular momentum in their respective shells, and couple to the highest possible spin which such configuration offers. The properties of stretched states are poorly known, even though they are of key importance for the physics of unbound systems.
The results of the experiment aiming at investigation of stretched single-particle state in 13C, which has been recently performed at the Cyclotron Centre Bronowice (CCB) at IFJ PAN in Kraków, will be presented. In light nuclei, such as 13C, stretched excitations appear as high-lying resonances and direct measurement of their properties such as, for example, decay patterns, should provide data, which may be used as a very demanding test of state-of-the-art theory approaches, from Shell Model Embedded in the Continuum to ab-initio type calculations. Here, investigations of the decay of the M4 resonance located at 21.47 MeV in 13C will be discussed. The experimental data were obtained by measuring inelastically scattered protons (which excite the resonance) on a 13C target in coincidence with charged particles from the resonance decay and gamma rays from daughter nuclei. In particular, emitted gamma rays give a precise knowledge of the feeding to specific states. The detection setup consisting of: i) the KRATTA telescope array, ii) an array of LaBr3 detectors, iii) two clusters of the PARIS scintillator array, and iv) a thick position-sensitive Si detector, was used.