Elastic scattering of 58 and 75 MeV photons by 12C and 16O and electromagnetic polarizabilities of the bound nucleon

Compton scattering from6Li at 60 MeV

“…This result gives confidence that the absolute cross-section extraction does not suffer from any unknown systematic effects. 16 O obtained by [18,19] and [20,21] and current results. Statistical errors are shown on the data points.…”

“…As such, the resonance locations have been fixed at 25 MeV and 34 MeV for the E1 and E2 resonances, and the widths were set to 12.0 and 16.0 MeV. The QD parameters have been fixed to the values listed in [19]. The resonance amplitudes obtained from the fit are listed in Table IV along with the fixed parameters, and the resulting cross section is shown as the solid curve in Figure 7.…”

“…Figure 6 shows the previous 16 O data from Lund [18,19] and the Saskatchewan Accelerator Laboratory (SAL) and University of Illinois collaboration [20,21]. The Lund data were collected at 58 MeV and the SAL/Illinois at 60 MeV.…”

“…Compton scattering measurements directly off the neutron are not possible due to the lack of a free neutron target. As such, experimenters have had to resort to using light nuclei such as [18][19][20][21] to try to measure α n and β n . The results for the heavier nuclei are ambiguous due to uncertainties in the model parameterizations.…”

Compton scattering fromC12using tagged photons in the energy range 65–115 MeV

“…[8] 12 C [9], [10], [11], [12], [13] 16 O [7], [8], [11], [12], [14], [15] 40 Ca [7], [9] It is also reasonable to ask whether the nucleon polarizabilities are modified when the proton or neutron is bound in a nucleus and, if so, to what degree. A multitude of Compton-scattering experiments have been carried out with a variety of light nuclei (see Table I) for the purpose of determining the bound-nucleon polarizabilities (α eff and β eff ) given by α eff = α N + ∆α, β eff = β N + ∆β, (6) where α N and β N are the nucleon-averaged free polarizabilities and ∆α and ∆β represent the nuclear modifications [13] which can be extracted from the scattering data.…”