Deuteron Compton scattering below pion photoproduction threshold

Abstract

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities is discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are needed for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.Comment: 48 pages, 16 figures, final version; discussion is slightly extended, a few references added, a figure for asymmetry is replace

Rearranging pionless effective field theory

“…7 at order Q 2 . The zero-range limit of T 1 coincides with previous computations [31,32]. The magnetic form factor is dominated by the diagrams shown in Fig.…”

“…(32). The contributions to Compton scattering from these higher dimension operators, as shown in Fig.…”

Compton scattering by the nucleon

“…12.0 ± 0.6 1.9 ∓ 0.6 13.9 ± 0.3 b) a) weighted average of the data in lines 2 and 3 b) the same as a) but constrained by the BL sum rule [10,11] lines 2 and 3 have a weighted average of α + β = 13.6 ± 1.1 which has to be compared with the BL sum-rule prediction…”

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

“…Similarly, the neutron polarizabilities have been extracted from measurements of 2 H(γ,γ) 2 H. They have been determined to be α n = 11.1 ± 1.8 stat ± 0.4 BSR ± 0.8 th β n = 4.1 ∓ 1.8 stat ± 0.4 BSR ± 0.8 th (4) preserving the BSR for the neutron [4] α n + β n = 15.2 ± 0.4.…”