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

TL;DR

This study investigates the structure of the proton-rich nucleus $^{23}$Al through measurements of momentum distributions and reaction cross sections, revealing a dominant d-wave configuration and ruling out a proton halo structure.

Contribution

The paper provides the first measurement of the momentum distribution of $^{22}$Mg fragments from $^{23}$Al breakup and analyzes the structure of $^{23}$Al using the Few-Body Glauber model.

Findings

Enhanced reaction cross section for $^{23}$Al compared to $^{24}$Al.

FWHM of momentum distribution is 232 1 28 MeV/c.

Dominant d-wave configuration indicates $^{23}$Al is not a proton halo nucleus.

Abstract

The longitudinal momentum distribution (P_{//}) of fragments after one-proton removal from ^{23} Al and reaction cross sections (\sigma_R) for ^{23,24} Al on carbon target at 74A MeV have been measured. The ^{23,24} Al ions were produced through projectile fragmentation of 135 A MeV ^{28} Si primary beam using RIPS fragment separator at RIKEN. P_{//} is measured by a direct time-of-flight (TOF) technique, while \sigma_R is determined using a transmission method. An enhancement in \sigma_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 \pm 28 MeV/c. The experimental data are discussed by using 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.