Coulomb Excitation of 26Ne

Abstract

Coulomb excitation of the exotic neutron‐rich nucleus 26Ne on a 208Pb target was measured at 58 A.MeV in order to search for low‐lying E1 strength above the neutron emission threshold. Data were also taken on an Al target to estimate the nuclear contribution. The radioactive beam was produced by fragmentation of a 95 A.MeV Ar beam delivered by the RIKEN Research Facility. The set‐up included a NaI gamma‐ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the 25Ne+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross‐section, a reduced dipole transition probability of B(E1)=0.49±0.16 e2fm2 is deduced. For the first time, the decay pattern of low‐lying strength in a neutron‐rich nucleus is measured.