1,720,977 research outputs found
Fixed-t subtracted dispersion relations for real Compton scattering off the nucleon
No full textFixed-t subtracted dispersion relations are presented for Compton scattering off the nucleon at energies Eγ<~500 MeV, as a formalism to extract the nucleon polarizabilities with a minimum of model dependence. The subtracted dispersion integrals are mainly saturated by πN intermediate states in the s channel, γN⃗πN⃗γN, and ππ intermediate states in the t channel, γγ⃗ππ⃗NN̅ . For the subprocess γγ⃗ππ, we construct a unitarized amplitude and find a good description of the available data. We show results for Compton scattering using the subtracted dispersion relations and display the sensitivity on the scalar polarizability difference α-β and the backward spin polarizability γπ, which enter directly as fit parameters in the present formalism. Double polarization observables are shown to have a unique potential for measuring the spin polarizabilities of the nucleon
Dispersion relation formalism for virtual Compton scattering and the generalized polarizabilities of the nucleon
No full textA dispersion relation formalism for the virtual Compton scattering (VCS) reaction on the proton is presented, which for the first time allows a dispersive evaluation of four generalized polarizabilities at a four-momentum transfer Q2<~0.5 GeV2. The dispersive integrals are calculated using a state-of-the-art pion photo- and electroproduction analysis. The dispersion formalism provides a new tool to analyze VCS experiments above pion threshold, thus increasing the sensitivity to the generalized polarizabilities of the nucleon
Dispersion relation formalism for real and virtual Compton scattering and nucleon polarizabilities
No full textWe report on fixed-t dispersion relations for Compton scattering off the nucleon at photon energies below 500 MeV, as s formalism to extract the nucleon polarizabilities. The dispersion relation framework is extended to the virtual Compton scattering in order to unravel the generalized polarizabilities of the nucleon
Dispersion relations in virtual Compton scattering
No full textWe describe the application of a dispersion-relation formalism to the virtual Compton scattering (VCS) reaction with the aim to extract
information on generalized polarizabilities from VCS observables over a large energy range
Compton scattering and the polarizabilities of the nucleon
No full textWe consider Compton scattering off the nucleon in the framework of fixed-t dispersion relations. The subtracted dispersion integrals are mainly saturated by pion-nucleon intermediate states in the s channel, and two-pion intermediate states in the t channel. In the present formalism the nucleon polarizabilities enter as subtraction constants to be determined by a fit to the Compton data. We show results for Compton scattering discussing in particular the sensitivity on the scalar polarizability difference alpha-beta and the backward spin polarizability gamma_pi
A dispersion theoretical approach to virtual Compton scattering off the proton
No full textWe present a dispersion relation formalism for virtual
Compton scattering (VCS) off the proton, which provides a new tool
to extract the generalized polarizabilities of the proton from VCS
observables over a large energy range
Dispersion relations formalism for virtual Compton scattering off the proton
No full textWe describe a dispersion relation formalism to the virtual Compton scattering reaction off the proton as a new tool to analyze VCS experiments above pion threshold, where one observes increasing effects of the generalized polarizabilities
Light-front interpretation of Proton Generalized Polarizabilities
Get PDFpeer reviewedWe extend the recently developed formalism to extract light-front quark charge densities from nucleon form factor data to the deformations of these quark charge densities when applying an external electric field. We show that the resulting induced polarizations can be extracted from proton generalized polarizabilities. The available data for the generalized electric polarizability of the proton yield a pronounced structure in its induced polarization at large transverse distances, which will be pinned down by forthcoming high precision virtual Compton scattering experiments
Dispersion analysis of the spin polarizabilities
No full textWe consider Compton scattering off the proton within a formalism
of fixed- subtracted dispersion relations which can be used to extract
the proton polarizabilities from data with a minimum of model dependence.
In addition we discuss the possibility to probe the proton structure
via the use of higher-order polarizabilities
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