Examining the exotic structure of the proton-rich nucleus $^{23}\mathrm{Al}$

Rapid Communication

Examining the exotic structure of the proton-rich nucleus ${}^{23}{Al}$

D. Q. Fang et al.

Phys. Rev. C 76, 031601(R) – Published 5 September 2007

Abstract

The longitudinal momentum distribution ( $P_{/ /}$ ) of fragments after one-proton removal from ${}^{23}{Al}$ and reaction cross sections ( $σ_{R}$ ) for ${}^{23, 24}{Al}$ on a carbon target at $74 A$ MeV have been measured. The ${}^{23, 24}{Al}$ ions were produced through projectile fragmentation of $135 A$ MeV ${}^{28}{Si}$ primary beam using the RIPS fragment separator at RIKEN. $P_{/ /}$ is measured by a direct time-of-flight (TOF) technique, while $σ_{R}$ is determined using a transmission method. An enhancement in $σ_{R}$ is observed for ${}^{23}{Al}$ compared with ${}^{24}{Al}$ . The $P_{/ /}$ for ${}^{22}{Mg}$ fragments from ${}^{23}{Al}$ breakup has been obtained for the first time. FWHM of the distributions has been determined to be 232 ± 28 MeV/ $c$ . The experimental data are discussed by using the Few-Body Glauber model. Analysis of $P_{/ /}$ demonstrates a dominant $d$ -wave configuration for the valence proton in ground state of ${}^{23}{Al}$ , indicating that ${}^{23}{Al}$ is not a proton halo nucleus.