Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions

Wimmer, K.; Bazin, D.; Gade, A.; Tostevin, J. A.; Baugher, T.; Chajęcki, Z.; Coupland, D.; Famiano, M.; Ghosh, T. K.; Grinyer, G. F.; Hodges, R.; Howard, M. E.; Kilburn, M.; Lynch, W. G.; Manning, B.; Meierbachtol, K.; Quarterman, Patrick; Ratkiewicz, A.; Sanetullaev, A.; Stroberg, S. R.; Tsang, M. B.; Weißhaar, D.; Winkelbauer, J.; Winkler, R.; Youngs, M.

doi:10.1103/physrevc.85.051603

Cited by 13 publications

(6 citation statements)

References 18 publications

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“…We now discuss and estimate the degree to which this approximation may overestimate the diffraction-stripping cross sections in these relatively light residue reactions; the dominant two-nucleon stripping mechanism will be unaffected. For two-proton knockout from 28 Mg, calculations using the present no-recoil approach reproduce the relative strengths of stripping and diffraction-stripping mechanisms within experimental errors [7]; the experimental and theoretical diffraction-stripping branching ratios were found to be b exp = 31(16)% and b th = 37.4%. Here, the recoil corrections for the light 12 C projectile will be considerably larger.…”

Section: Recoil Effectsmentioning

confidence: 59%

“…A feature of this model description is that the removal cross sections involve only elastic interactions of the projectile residues with the target but sums of contributions from both elastic and inelastic interactions of one or both nucleons with the target [6]. New data, for the sd-shell nucleus 28 Mg and the 28 Mg(−2p) reaction, have quantified these different contributions experimentally [7] and have confirmed that the relative importance of these different processes to the cross sections are consistent with the predictions of the eikonal dynamical model. This has provided an important additional test of the reaction model.…”

Section: Introductionmentioning

confidence: 99%

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Microscopic two-nucleon overlaps and knockout reactions from12C

et al. 2012

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The nuclear structure dependence of direct reactions that remove a pair of like or unlike nucleons from a fast 12 C projectile beam are considered. Specifically, we study the differences in the two-nucleon correlations present and the predicted removal cross sections when using p-shell shell-model and multi-hω no-core shell-model (NCSM) descriptions of the two-nucleon overlaps for the transitions to the mass A = 10 projectile residues. The NCSM calculations use modern chiral two-nucleon and three-nucleon (NN + 3N) interactions. The np-removal cross sections to low-lying T = 0, 10 B final states are enhanced when using the NCSM two-nucleon amplitudes. The calculated absolute and relative partial cross sections to the low-energy 10 B final states show a significant sensitivity to the interactions used, suggesting that assessments of the overlap functions for these transitions and confirmations of their structure could be made using final-state-exclusive measurements of the np-removal cross sections and the associated momentum distributions of the forward traveling projectile-like residues.

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Section: Recoil Effectsmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Microscopic two-nucleon overlaps and knockout reactions from12C

et al. 2012

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“…The HiRA array covered polar angles (ϑ) from 9 • to 56 • and for a given value of ϑ up to 40% of the azimuthal angles were covered. A correction for the limited azimuthal acceptance within the ϑ range was applied following our previous work [16].…”

Section: Methodsmentioning

confidence: 99%

Elastic breakup cross sections of well-bound nucleons

et al. 2014

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The 9 Be( 28 Mg, 27 Na) one-proton removal reaction with a large proton separation energy of Sp( 28 Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27 Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the removal of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

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“…2(f) shows the experimental partial cross sections extracted for states in 22 Mg compared to the cross sections calculated using the USD TNAs. Previous work on two-nucleon knockout [4][5][6]34] has found a ratio of approximately 0.5 between experimental and theoretical in- (8), and 0.62(11), respectively. Interestingly, the experimental cross section for the 2 + 1 state is 0.31(11) mb while the theoretical prediction is 0.117 mb.…”

Section: (20) Kev [11]mentioning

confidence: 99%

Two-neutron knockout as a probe of the composition of states in Mg22,Al23 , and Si<

et al. 2020

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Simpson and Tostevin proposed that the width and shape of exclusive parallel momentum distributions of the A − 2 residue in direct two-nucleon knockout reactions carry a measurable sensitivity to the nucleon single-particle configurations and their couplings within the wave functions of exotic nuclei. We report here on the first benchmarks and use of this new spectroscopic tool. Exclusive parallel momentum distributions for states in the neutron-deficient nuclei 22 Mg, 23 Al, and 24 Si populated in such direct two-neutron removal reactions were extracted and compared to predictions combining eikonal reaction theory and shell-model calculations. For the well-known 22 Mg and 23 Al nuclei, measurements and calculations were found to agree, supporting the dependence of the parallel momentum distribution width on the angular momentum composition of the shell-model two-neutron amplitudes. In 24 Si, a level at 3439(9) keV, of relevance for the important 23 Al(p,γ) 24 Si astrophysical reaction rate, was confirmed to be the 2 + 2 state, while the 4 + 1 state, expected to be strongly populated in two-neutron knockout, was not observed. This puzzle is resolved by theoretical considerations of the Thomas-Ehrman shift, which also suggest that a previously reported 3471-keV state in 24 Si is in fact the (0 + 2) level with one of the largest experimental mirror-energy shifts ever observed.

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Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions

Cited by 13 publications

References 18 publications

Microscopic two-nucleon overlaps and knockout reactions from12C

Microscopic two-nucleon overlaps and knockout reactions from12C

Elastic breakup cross sections of well-bound nucleons

Two-neutron knockout as a probe of the composition of states in Mg22,Al23 , and Si<

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