Identification of a new low-lying state in the proton drip line nucleus Na-19

The second excited state (J(pi)=1/2(+), l=0) of the proton-rich nucleus Na-19 has been observed for the first time using the elastic scattering reaction H-1(Ne-18,H-1)Ne-18. An intense (4x10(6) pps) Ne-18 radioactive beam was produced at the CRC-RIB facility at Louvain-la-Neuve to bombard a polyethylene target. The recoil protons were detected at 20 different angles in the LEDA segmented silicon detector. The resulting elastic scattering cross sections have been analyzed using a global R-matrix fit. We find that the second excited state in Na-19 lies at the center-of-mass energy E-c.m.=1.066+/-0.003 MeV with respect to the Ne-18+p threshold, and has a proton width Gamma(p)=101+/-3 keV. The Coulomb shift between the 1/2(+) mirror levels in O-19 and Na-19 is 0.73 MeV, among the largest values currently observed in light exotic nuclei.