Quasi-free Compton Scattering and the Polarizabilities of the Neutron

Abstract

Differential cross sections for quasi-free Compton scattering from the proton and neutron bound in the deuteron have been measured using the Glasgow/Mainz tagging spectrometer at the Mainz MAMI accelerator together with the Mainz 48 cm $\oslash$ $\times$ 64 cm NaI(Tl) photon detector and the Göttingen SENECA recoil detector. The data cover photon energies ranging from 200 MeV to 400 MeV at ${\theta }_{\gamma }^{LAB}=136.2^{\circ }$. Liquid deuterium and hydrogen targets allowed direct comparison of free and quasi-free scattering from the proton. The neutron detection efficiency of the SENECA detector was measured via the reaction $p(\gamma ,{\pi }^{+}n)$. The "free" proton Compton scattering cross sections extracted from the bound proton data are in reasonable agreement with those for the free proton which gives confidence in the method to extract the differential cross section for free scattering from quasi-free data. Differential cross sections on the free neutron have been extracted and the difference of the electromagnetic polarizabilities of the neutron have been obtained to be $\alpha -\beta =9.8\pm 3.6(stat){}_1^{2.1}.1(syst)\pm 2.2(model)$ in units $10^{-4}f{m}^3$. In combination with the polarizability sum $\alpha +\beta =15.2\pm 0.5$ deduced from photoabsorption data, the neutron electric and magnetic polarizabilities, ${\alpha }_n=12.5\pm 1.8(stat){}_{-0.6}^{+1.1}\pm 1.1(model)$ and ${\beta }_n=2.7\mp 1.8(stat){}_{-1.1}^{+0.6}(syst)\mp 1.1(model)$ are obtained. The backward spin polarizability of the neutron was determined to be ${\gamma }_{\pi }^{(n)}=(58.6\pm 4.0)\times 10^{-4}f{m}^4$.

Cited by in corpus (35)

• Electromagnetic Form Factors of the Nucleon and Compton Scattering
• Using effective field theory to analyse low-energy Compton scattering data from protons and light nuclei
• Nucleon Polarizabilities: from Compton Scattering to Hydrogen Atom
• The Magnetic Structure of Light Nuclei from Lattice QCD
• Signatures of Chiral Dynamics in Low Energy Compton Scattering off the Nucleon
• Compton scattering on the proton, neutron, and deuteron in chiral perturbation theory to O(Q^4)
• Magnetic properties of the nucleon in a uniform background field
• New Measurement of Compton Scattering from the Deuteron and an Improved Extraction of the Neutron Electromagnetic Polarizabilities
• Two-photon exchange correction to the Lamb shift and hyperfine splitting of S levels
• Hadron Polarizabilities
• Predictions of covariant chiral perturbation theory for nucleon polarisabilities and polarised Compton scattering
• Sea contributions to the electric polarizability of the hadrons
• Evidence for Narrow N*(1685) Resonance in Quasifree Compton Scattering on the Neutron
• Finite-volume and partial quenching effects in the magnetic polarizability of the neutron
• Nucleon Polarisabilities at and Beyond Physical Pion Masses
• Model-independent effects of Delta excitation in nucleon polarizabilities
• Magnetic polarisability of the nucleon using a Laplacian mode projection
• Spin Polarizabilities of the Nucleon from Polarized Low Energy Compton Scattering
• Explicit Delta(1232) Degrees of Freedom in Compton Scattering off the Deuteron
• Compton Scattering from the Deuteron below Pion-Production Threshold
• Neutron magnetic polarisability with Landau mode operators
• Investigating Neutron Polarizabilities through Compton Scattering on ${}^3$He
• Analyzing the Effects of Neutron Polarizabilities in Elastic Compton Scattering off ${}^3$He
• Nucleon Polarizabilities from Deuteron Compton Scattering within a Green's-Function Hybrid Approach
• Dispersion theory of nucleon Compton scattering and polarizabilities
• Predictions for Polarized-Beam/Vector-Polarized-Target Observables in Elastic Compton Scattering on the Deuteron
• Chiral Effective Theory Methods and their Application to the Structure of Hadrons from Lattice QCD
• Elastic Compton Scattering from 3He and the Role of the Delta
• Quasi-free ${\pi }^0$ Photoproduction from the Bound Nucleon
• Dipole-dipole dispersion interactions between neutrons
• Elementary quantum mechanics of the neutron with an electric dipole moment
• Nucleon Spin-Polarisabilities from Polarisation Observables in Low-Energy Deuteron Compton Scattering
• Magnetic Polarisability of Octet Baryons via Lattice QCD
• Compton Scattering by the Nucleon
• Few-neutron systems with the long-range Casimir-Polder force