Parity-transfer (16O, 16F(0−, g.s.)) reaction as a selective probe of isovector 0− states in nuclei

We demonstrate that the parity-transfer (16O, 16F(0−, g.s.)) reaction provides a selective probe of isovector 0− excitations in nuclei. This reaction selectively populates unnatural-parity states through a 0+ → 0− transition in the projectile. The excitation-energy spectrum of 12B was reconstructed via the 12C(16O, 16F(0−, g.s.)) reaction at 247 MeV/u from the coincident detection of the 15O + p decay products of 16F. The known 0− state at Ex = 9.3MeV was clearly observed with an enhanced forward cross section, confirming the selectivity of the reaction. The structures observed at Ex = 6.6 ± 0.4 and 14.8 ± 0.3MeV exhibit forward-peaked angular distributions and are suggested to contain significant 0− strength. These results demonstrate that the parity-transfer reaction provides a powerful probe of 0− excitations and highlight its potential for systematic studies of spin-isospin modes, including pion-related dynamics, in nuclei.