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We discuss low-energy virtual Compton scattering off the proton within the framework of a nonrelativistic constituent quark model. A simple interpretation of the spin-averaged generalized polarizabilities is given in terms of the induced…

Nuclear Theory · Physics 2017-08-23 B. Pasquini , S. Scherer , D. Drechsel

We study low-energy nucleon Compton scattering in the framework of baryon chiral perturbation theory (B$\chi$PT) with pion, nucleon, and $\Delta$(1232) degrees of freedom, up to and including the next-to-next-to-leading order (NNLO). We…

High Energy Physics - Phenomenology · Physics 2010-01-06 V. Lensky , V. Pascalutsa

We present the first attempt to extract the scalar dipole dynamical polarizabilities from proton real Compton scattering data below pion-production threshold. The theoretical framework combines dispersion relations technique, low-energy…

High Energy Physics - Phenomenology · Physics 2018-07-25 B. Pasquini , P. Pedroni , S. Sconfietti

The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The chi_PT effective Lagrangian, using data from radiative…

High Energy Physics - Experiment · Physics 2007-05-23 Murray Moinester

We discuss the most general form of the electromagnetic vertex of an off-shell pion. The framework of chiral perturbation theory is used to illustrate the representation dependence of the electromagnetic three-point Green's function. For…

Nuclear Theory · Physics 2007-05-23 S. Scherer

The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The pion polarizabilities are key observables, and provide…

High Energy Physics - Experiment · Physics 2008-11-26 Murray Moinester

We calculate the amplitude T_1 for forward doubly-virtual Compton scattering in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the gammaNDelta form factor. This provides…

High Energy Physics - Phenomenology · Physics 2012-12-12 Michael C. Birse , Judith A. McGovern

We study low-energy virtual Compton scattering off the proton within the framework of a nonrelativistic constituent quark model. The Compton tensor is divided into two separately gauge-invariant contributions. The first consists of the…

Nuclear Theory · Physics 2011-07-19 B. Pasquini , S. Scherer , D. Drechsel

As guideline for forthcoming experiments, we present predictions from Chiral Effective Field Theory for polarized cross sections in low energy Compton scattering for photon energies below 170 MeV, both on the proton and on the neutron.…

Nuclear Theory · Physics 2009-11-10 Robert P. Hildebrandt , Harald W. Griesshammer , Thomas R. Hemmert

Goal of this work is the consistent description of elastic Compton scattering from the single nucleon and the deuteron. The theoretical framework chosen is Chiral Perturbation Theory, which is the low-energy formulation of Quantum…

Nuclear Theory · Physics 2007-05-23 Robert P. Hildebrandt

The Compton double-polarization observable $\Sigma_{2z}$ has been measured for the first time in the $\Delta(1232)$ resonance region using a circularly polarized photon beam incident on a longitudinally polarized target at the Mainz…

We consider Compton scattering by a pion in the framework of chiral perturbation theory. We investigate off--shell effects in the s-- and u--channel pole diagrams. For that purpose we perform a field transformation which, in comparison with…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Scherer , H. W. Fearing

Differential cross section of deuteron Compton scattering has been calculated using the Bonn NN-potential, a consistent set of meson-exchange currents and seagulls, and lowest- and higher-order electromagnetic polarizabilities of the…

Nuclear Theory · Physics 2009-11-06 M. I. Levchuk , A. I. L'vov

We compute the Compton scattering off the nucleons in the framework of manifestly covariant baryon chiral perturbation theory (B$\chi$PT). The results for observables differ substantially from the corresponding calculations in heavy-baryon…

Nuclear Theory · Physics 2009-04-17 Vadim Lensky , Vladimir Pascalutsa

Compton scattering offers a unique opportunity to study the dynamical structure of hadrons over a wide kinematic range, with polarizabilities characterizing the hadron active internal degrees of freedom. We present calculations and detailed…

High Energy Physics - Phenomenology · Physics 2013-01-09 A. Aleksejevs , S. Barkanova

We present a calculation of the fourth-order (NLO) contribution to spin-dependent Compton scattering in heavy-baryon chiral perturbation theory, and we give results for the four spin polarisabilities. No low-energy constants, except for the…

High Energy Physics - Phenomenology · Physics 2009-10-31 K. B. Vijaya Kumar , Judith A. McGovern , Michael C. Birse

The Compton scattering on a charged pion and the process \gamma\gamma \to \pi^0\pi^0 are studied using the dispersion relations. Unknown parameters of the S-wave \pi\pi interaction, represented as a board Breit-Wignar resonance, and a sum…

Nuclear Theory · Physics 2011-07-19 L. V. Fil'kov , V. L. Kashevarov

Compton scattering from the proton was investigated at s=6.9 (GeV/c)**2 and \t=-4.0 (GeV/c)**2 via polarization transfer from circularly polarized incident photons. The longitudinal and transverse components of the recoil proton…

Nuclear Experiment · Physics 2008-11-26 D. J. Hamilton , V. H. Mamyan , the Jefferson Lab Hall A Collaboration

We discuss the virtual Compton scattering amplitude $\gamma^\ast+\pi\to \gamma+\pi$ which enters the reaction $\pi^-+e^-\to\pi^-+e^-+\gamma$. The low-energy scattering amplitude is divided into a model-independent part, involving only the…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Scherer

The subject of low energy polarized Compton scattering from the proton, which is characterized by phenomenological spin-polarizabilities, is introduced and connection is made to new theoretical and experimental developments which were…

Nuclear Theory · Physics 2017-08-23 Barry R. Holstein