Experimental Research on Two-Proton Emissions from the Excited States of Proton-Rich Nuclei Close to the Drip Line

Abstract

A series of experiments have been performed by complete-kinematics measurements at HIRFL-RIBLL facility to research two-proton (2p) emissions from the excited states of proton-rich nuclei close to the drip line, such as 17,18 Ne, 28,29 S, and 27,28 P. With helps of Monte-Carlo simulations, obvious branches of 2 He decay were observed in even-Z nuclei 28,29 S but not in odd-Z nuclei 27,28 P, indicating that 2p skin/halo structures are responsible for 2p correlated emissions. The contrastive researches show that there exists a link between excited-state emission and ground state configuration. Moreover, distances between two valence protons in 17,18 Ne have been derived by HBT analyses. The 2p opening angle in 17 Ne is determined as 74.5, implying that the BCS/BEC crossover may occur in the surroundings of low density matter.