Different mechanism of two-proton emission from proton-rich nuclei 23Al and 22Mg

• Published in: Physics letters. B 2015-04, Vol.743, p.306-309
• Main Authors: Ma, Y.G., Fang, D.Q., Sun, X.Y., Zhou, P., Togano, Y., Aoi, N., Baba, H., Cai, X.Z., Cao, X.G., Chen, J.G., Fu, Y., Guo, W., Hara, Y., Honda, T., Hu, Z.G., Ieki, K., Ishibashi, Y., Ito, Y., Iwasa, N., Kanno, S., Kawabata, T., Kimura, H., Kondo, Y., Kurita, K., Kurokawa, M., Moriguchi, T., Murakami, H., Ooishi, H., Okada, K., Ota, S., Ozawa, A., Sakurai, H., Shimoura, S., Shioda, R., Takeshita, E., Takeuchi, S., Tian, W.D., Wang, H.W., Wang, J.S., Wang, M., Yamada, K., Yamada, Y., Yasuda, Y., Yoneda, K., Zhang, G.Q., Motobayashi, T.
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2015.02.066

Two-proton relative momentum (qpp) and opening angle (θpp) distributions from the three-body decay of two excited proton-rich nuclei, namely Al23→p+p+Na21 and Mg22→p+p+Ne20, have been measured with the projectile fragment separator (RIPS) at the RIKEN RI Beam Factory. An evident peak at qpp∼20 MeV/c as well as a peak in θpp around 30° are seen in the two-proton break-up channel from a highly-excited 22Mg. In contrast, such peaks are absent for the 23Al case. It is concluded that the two-proton emission mechanism of excited 22Mg is quite different from the 23Al case, with the former having a favorable diproton emission component at a highly excited state and the latter dominated by the sequential decay process.