The neturon rich nucleus 13B was studied via the proton transfer reaction 4He(12Be,13B \gamma) at 50AMeV. The known 4.83-MeV excited state was strongly populated and its spin and parity were assigned to 1/2+ by comparing the angular differential cross section data with DWBA calculations. This low-lying 1/2+ state is interpreted as a proton intruder state and indicates a deformation of the nucleus.
@article{arxiv.0807.0478,
title = {Low-lying Proton Intruder State in 13B},
author = {S. Ota and S. Shimoura and H. Iwasaki and M. Kurokawa and S. Michimasa and N. Aoi and H. Baba and K. Demichi and Z. Elekes and T. Fukuchi and T. Gomi and S. Kanno and S. Kubono and K. Kurita and H. Hasegawa and E. Ideguchi and N. Iwasa and Y. U. Matsuyama and K. L. Yurkewicz and T. Minemura and T. Motobayashi and T. Murakami and M. Notani and A. Odahara and A. Saito and H. Sakurai and E. Takeshita and S. Takeuchi and M. Tamaki and T. Teranishi and Y. Yanagisawa and K. Yamada and M. Ishihara},
journal= {arXiv preprint arXiv:0807.0478},
year = {2008}
}