Mirrored one-nucleon knockout reactions to the T-z = +/- 3/2 A=53 mirror nuclei

Background: The study of excited states in mirror nuclei allows us to extract information on charge-dependent (i.e., isospin-nonconserving) interactions in nuclei. Purpose: To extend previous studies of mirror nuclei in the f(7/2) region, investigating charge symmetry breaking of the strong nuclear force. Methods: gamma-ray spectroscopy has been performed for the mirror (T-z = +/- 3/2) pair Ni-53 and Mn-53, produced via mirrored one-nucleon knockout reactions. Results: Several new transitions have been identified in Ni-53 from which a new level scheme has been constructed. Cross sections for knockout have been analyzed and compared with reaction model calculations where evidence is found for knockout from high-spin isomeric states. Mirror energy differences between isobaric analog states have been computed, compared to large scale shell-model calculations, and interpreted in terms of isospin-nonconserving effects. In addition, lifetimes for the long-lived J(pi) = 5(-)/21 analog states in both Mn-53 and Ni-53 have been extracted through lineshape analysis, giving half-lives of t(1/2) = 120 (14) ps and t(1/2) = 198 (12) ps, respectively. Conclusions: The inclusion of a set of isovector isospin-nonconserving matrix elements to the shell-model calculations gave the best agreement with the experimental data.