Antiprotonic studies of nuclear neutron halos

Wycech, S.; Skalski, Janusz; Smolańczuk, R.; Dobaczewski, J.; Rook, J.R.

doi:10.1103/physrevc.54.1832

Cited by 35 publications

(50 citation statements)

References 48 publications

(95 reference statements)

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“…It is this energy release that allows to use the closure approximation over the final nuclear states. As a consequence one can obtain [53] a semi-classical formula for the partial absorption width on a single nucleon i,…”

Section: B Antiproton-nucleus Interactionmentioning

confidence: 99%

“…For the details of final state calculations and the derivation of the intuitively simple formula (1), we refer to Ref. [53]. One problem in the analysis of halo factors is to know the atomic state from which nuclear capture takes place.…”

Section: B Antiproton-nucleus Interactionmentioning

confidence: 99%

“…However, the only large exception, the 176 Yb nucleus, for which the annihilation site seems to be located much farther away from the nucleus than predicted by calculations needs further studies (cf. [53]). Figure 12 shows a comparison between the experimentally determined and calculated values of the halo factor.…”

Section: Annihilation Sitementioning

confidence: 99%

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Composition of the nuclear periphery from antiproton absorption

et al. 1998

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Thirteen targets with mass numbers from 58 to 238 were irradiated with the antiproton beam from the Low Energy Antiproton Ring facility at CERN leading to the formation of antiprotonic atoms of these heavy elements. The antiproton capture at the end of atomic cascade results in the production of more or less excited residual nuclei. The targets were selected with the criterion that both reaction products with one nucleon less than the proton and neutron number of the target are radioactive. The yield of these radioactive products after stopped-antiproton annihilation was determined using gamma-ray spectroscopy techniques. This yield is related to the proton and neutron density in the target nucleus at radial distance corresponding to the antiproton annihilation site. The experimental data clearly indicate the existence of a neutron rich nuclear periphery, a "neutron halo", strongly correlated with the target neutron separation energy Bn, and observed for targets with Bn < 10 MeV. For two target nuclei, 106 Cd and 144 Sm, with larger neutron binding energies a proton rich nuclear periphery was observed. Most of the experimental data are in reasonable agreement with calculations based on current antiproton-nucleus and pion-nucleus interaction potentials and on nuclear densities deduced with the help of the Hartree-Fock-Bogoliubov approach. This approach was, however, unable to account for the 106 Cd and 144 Sm results.

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Section: B Antiproton-nucleus Interactionmentioning

confidence: 99%

Section: B Antiproton-nucleus Interactionmentioning

confidence: 99%

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Composition of the nuclear periphery from antiproton absorption

et al. 1998

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“…First, using the so-called radiochemical method, we investigated [1][2][3][4] the ratios of peripheral neutron to proton densities at distances around 2.5 fm larger than the nuclear charge half-density radius [5]. The method involved measuring the yield of radioactive nuclei having one proton or one neutron less than the target nucleus, produced after antiproton capture, cascade, and annihilation in the target antiprotonic atom.…”

Section: Introductionmentioning

confidence: 99%

“…We assume and show by a comparison with model calculations that charge, proton, and neutron distributions in this nucleus can be well approximated by two-parameter Fermi (2pF) distributions: ρ(r) = ρ 0 {1 + exp( r−c a )} −1 , where c is the half-density radius, a is the diffuseness parameter, and ρ 0 is a normalization factor. In particular, calculating the neutron rms radius from the antiprotonic x-ray data sensitive to densities at distances around 1.5 fm larger than the half-density charge radius [5], we extrapolate the experimental density well into the interior of the nucleus. As shown below (Sec.…”

Section: A Introductory Statementsmentioning

confidence: 99%

Neutron density distributions from antiprotonicPb208andBi209

Kłos¹,

et al. 2007

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The x-ray cascade from antiprotonic atoms was studied for 208 Pb and 209 Bi. Widths and shifts of the levels due to the strong interaction were determined. Using modern antiproton-nucleus optical potentials, the neutron densities in the nuclear periphery were deduced. Assuming two-parameter Fermi distributions (2pF) describing the proton and neutron densities, the neutron rms radii were deduced for both nuclei. The difference of neutron and proton rms radii r np equal to 0.16 ± (0.02) stat ± (0.04) syst fm for 208 Pb and 0.14 ± (0.04) stat ± (0.04) syst fm for 209 Bi were determined, and the assigned systematic errors are discussed. The r np values and the deduced shapes of the neutron distributions are compared with mean field model calculations.

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Nuclear periphery studied with antiprotonic atoms

Trzcińska¹

2009

Exa/Leap 2008

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Antiprotonic studies of nuclear neutron halos

Cited by 35 publications

References 48 publications

Composition of the nuclear periphery from antiproton absorption

Composition of the nuclear periphery from antiproton absorption

Neutron density distributions from antiprotonicPb208andBi209

Nuclear periphery studied with antiprotonic atoms

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