Decay of 1, 2 and 3-phonon states in 40Ca Original Research Article

Inelastic scattering of 40Ca on 40Ca at 50 A.MeV has been measured in coincidence with protons at the GANIL facility using a very performant set-up. The SPEG spectrometer was associated with 240 CsI(Tl) scintillators of the INDRA 4π array, allowing for the measurement of complete decay events. The missing energy method was applied to these events to study the particle decay of collective states. For events with excitation energy between 42 and 55 MeV, a direct decay branch by three protons towards the low energy states of 37Cl gives the first evidence for a 3-phonon giant resonance state. A significant direct decay branch by alpha-particles of the GQR is also measured for the first time.