No abstract

Differential cross sections for Compton scattering from the proton have been measured at scattering angles of 55°, 90°, and 125°in the laboratory frame using quasimonoenergetic linearly (circularly) polarized photon beams with a weighted mean energy value of 83.4 MeV (81.3 MeV). These measurements were performed at the High Intensity Gamma-Ray Source facility at the Triangle Universities Nuclear Laboratory. The results are compared to previous measurements and are interpreted in the chiral effective field theory framework to extract the electromagnetic dipole polarizabilities of the proton, which gives α p E1 = 13.8 ± 1.2stat ± 0.1BSR ± 0.3 theo , β p M 1 = 0.2 ∓ 1.2stat ± 0.1BSR ∓ 0.3 theo in units of 10 −4 fm 3 .

Differential cross sections for elastic Compton scattering from 4 He have been measured with high statistical precision at the High Intensity γ-ray Source at laboratory scattering angles of 55°, 90°, and 125°using a quasi-monoenergetic photon beam with a weighted mean energy value of 81.3 MeV. The results are compared to previous measurements and similar fore-aft asymmetry in the angular distribution of the differential cross sections is observed. This experimental work is expected to strongly motivate the development of effective-field-theory calculations of Compton scattering from 4 He to fully interpret the data.

No abstract