Excited states in 38,40,42Si nuclei have been studied via in-beam gamma-ray spectroscopy with multi-nucleon removal reactions. Intense radioactive beams of 40S and 44S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled gamma-gamma coincidence measurements. A prominent gamma line observed with an energy of 742(8) keV in 42Si confirms the 2+ state reported in an earlier study. Among the gamma lines observed in coincidence with the 2+ -> 0+ transition, the most probable candidate for the transition from the yrast 4+ state was identified, leading to a 4+_1 energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2+_1 and 4+_1 states indicates well-developed deformation in 42Si at N=28 and Z=14. Also for 38,40Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for 42Si, the results show a rapid deformation development of Si isotopes from N=24 to N=28.
@article{arxiv.1207.6191,
title = {Well-developed deformation in 42Si},
author = {S. Takeuchi and M. Matsushita and N. Aoi and P. Doornenbal and K. Li and T. Motobayashi and H. Scheit and D. Steppenbeck and H. Wang and H. Baba and D. Bazin and L. Càceres and H. Crawford and P. Fallon and R. Gernhäuser and J. Gibelin and S. Go and S. Grévy and C. Hinke and C. R. Hoffman and R. Hughes and E. Ideguchi and D. Jenkins and N. Kobayashi and Y. Kondo and R. Krücken and T. Le Bleis and J. Lee and G. Lee and A. Matta and S. Michimasa and T. Nakamura and S. Ota and M. Petri and T. Sako and H. Sakurai and S. Shimoura and K. Steiger and K. Takahashi and M. Takechi and Y. Togano and R. Winkler and K. Yoneda},
journal= {arXiv preprint arXiv:1207.6191},
year = {2015}
}