In-beam gamma-ray spectroscopy at the proton dripline: 23Al

Abstract

We report on the first in-beam $\gamma$-ray spectroscopy of \nuc{23}{Al} using two different reactions at intermediate beam energies: inelastic scattering off \nuc{9}{Be} and heavy-ion induced one-proton pickup, \nuc{9}{Be}(\nuc{22}{Mg},\nuc{23}{Al}$+\gamma$)X, at 75.1 MeV/nucleon. A $\gamma$-ray transition at 1616(8) keV -- exceeding the proton separation energy by 1494 keV -- was observed in both reactions. From shell model and proton decay calculations we argue that this $\gamma$-ray decay proceeds from the core-excited $7/2^{+}$ state to the $5/2^{+}$ ground state of \nuc{23}{Al}. The proposed nature of this state, $[\nuc{22}{Mg}(2^+_1) \otimes πd_{5/2}]_{7/2+}$, is consistent with the presence of a gamma-branch and with the population of this state in the two reactions.

arXiv commentPhysics Letters B, accepted

References in corpus (1)

• Neutrino Capture Cross Sections for Ar-40 and beta-decay of Ti-40

Cited by in corpus (11)

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• Structure of 23Al from one-proton breakup reaction and astrophysical implications
• Proton-proton correlations in distinguishing the two-proton emission mechanism of ${}^{23}$Al and ${}^{22}$Mg
• Two-neutron knockout as a probe of the composition of states in ${}^{22}$Mg, ${}^{23}$Al, and ${}^{24}$Si
• Inverse-kinematics one-neutron pickup with fast rare-isotope beams
• Exploiting dissipative reactions to perform in-beam $\gamma$-ray spectroscopy of the neutron-deficient isotopes \nuc{38,39}{Ca}
• In-beam $\gamma$-ray spectroscopy at the proton dripline: ${}^{40}$Sc
• Structure of ${}^{23}$Al from a multi-channel algebraic scattering model based on mirror symmetry
• Mass-15 nuclei and predicting narrow states beyond the proton drip line
• Intermediate-energy inverse-kinematics one-proton pickup reactions on neutron-deficient $fp$-shell nuclei