First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus:Ni56

Isoscalar response ofNi68toα-particle and deuteron probes

“…In the 68 Ni(d,d') 68 Ni * reaction, the background is dominated by deuteron breakup [14]. Indeed, considering the charge resolution, it was not possible to distinguish scattered deuterons from inelastic scattering 68 Ni(d,d') and protons from deuteron breakup 68 Ni(d,p).…”

“…The ISGMR has been measured at 19.3 ± 0.5 MeV and the isoscalar giant quadrupole resonance (ISGQR) at 16.2 ± 0.5 MeV [14]. The isoscalar giant dipole resonance (ISGDR), a second-order mode corresponding to the so-called squeezing mode [8,9], has never been measured in an unstable nucleus.…”

“…Measuring the scattering of radioactive nuclei from light probes requires the use of inverse kinematics and the detection of very low-energy light charged particles. Therefore, a pioneering technique, using an active target as a detector and the missing-mass method, has been developed for measuring the ISGR with a deuteron probe [14]. This innovative technique has been used again for the present experiment and will be described below.…”

“…These are i) to understand the evolution of the nuclear-matter incompressibility along an isotopic chain, and ii) to check for the prediction of a soft monopole mode as well as the prediction of a soft isoscalar dipole mode in neutron-rich nuclei. As a soft monopole mode is predicted in 68 Ni [4,5,7] and as the only measurement of ISGR in an unstable nucleus has been done in 56 Ni [14], 68 Ni is a nucleus of choice in order to address these questions. Therefore, we present here the first measurement of the isoscalar giant resonances in a neutron-rich unstable nucleus, 68 Ni.…”

Giant monopole resonance in Pb isotopes

“…Experimentally, the measurement of the GMR on an isotopic chain facilitates the study of superfluidity on the GMR properties [3], and the possibility to measure the GMR in unstable nuclei emphasizes this feature [9]. It is therefore necessary to go towards the measurement of the GMR on several nuclei, such as an isotopic chain.…”