Compton scattering of 87 MeV photons by ^{4}He
Abstract
Differential cross sections for Compton scattering by ^{4}He have been measured at photon energies ranging from 83.7 to 93.8 MeV with a weighted average of 87 MeV using the bremsstrahlung beam of the MAXLAB (Lund) nuclearphysics facility. The experimental differential cross sections show a pronounced increase at backward angles, strongly differing from predictions based on zeroangle dispersion relations and on the standard method used to calculate the differential cross section at nonzero angles. It is shown that the attempt to explain this effect in terms of quadrupole strength leads to unreasonable properties of the photoabsorption cross section. A parametrization in terms of a shift in the multipolarity ratio of the electromagnetic polarizabilities of the bound nucleon leads to Δβ =  Δα = 7 × 10 ^{4} fm ^{3}.
 Publication:

Nuclear Physics A
 Pub Date:
 February 1995
 DOI:
 10.1016/03759474(95)001773
 Bibcode:
 1995NuPhA.591....1F