Proton-proton correlations in distinguishing the two-proton emission   mechanism of $^{23}$Al and $^{22}$Mg
  The proton-proton momentum correlation functions ($C_{pp}(q)$) for kinematically complete decay channels of $^{23}$Al $\rightarrow$ p + p + $^{21}$Na and $^{22}$Mg $\rightarrow$ p + p + $^{20}$Ne have been measured at the RIKEN RI Beam Factory. From the very different correlation strength of $C_{pp}(q)$ for $^{23}$Al and $^{22}$Mg, the source size and emission time information were extracted from the $C_{pp}(q)$ data by assuming a Gaussian source profile in the correlation function calculation code (CRAB). The results indicated that the mechanism of two-proton emission from $^{23}$Al was mainly sequential emission, while that of $^{22}$Mg was mainly three-body simultaneous emission. By combining our earlier results of the two-proton relative momentum and the opening angle, it is pointed out that the mechanism of two-proton emission could be distinguished clearly. 
D. Q. Fang, Y. G. Ma, X. Y. Sun, P. Zhou, Y. Togano, N. Aoi, H. Baba,   X. Z. Cai, X. G. Cao, J. G. Chen, Y. Fu, W. Guo, Y. ...
nucl-ex nucl-th