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We analyze virtual Compton scattering off the nucleon at low energies in a covariant, model-independent formalism. We define a set of invariant functions which, once the irregular nucleon pole terms have been subtracted in a gauge-invariant…

Nuclear Theory · Physics 2008-11-26 D. Drechsel , G. Knoechlein , A. Yu. Korchin , A. Metz , S. Scherer

We calculate the spin-averaged amplitude for doubly virtual forward Compton scattering off nucleons in the framework of manifestly Lorentz invariant baryon chiral perturbation theory at complete one-loop order $O(p^4)$. The calculations are…

High Energy Physics - Lattice · Physics 2021-02-24 J. Lozano , A. Agadjanov , J. Gegelia , U. -G. Meißner , A. Rusetsky

We report on a calculation to show that the Fourier transform of the Deeply Virtual Compton Scattering (DVCS) amplitude with respect to the skewness variable \zeta at fixed invariant momentum transfer squared t gives results that are…

High Energy Physics - Phenomenology · Physics 2008-11-26 Asmita Mukherjee

The longitudinal target-spin asymmetry A_UL for the exclusive electroproduction of high energy photons was measured for the first time in p(e,e'p\gamma). The data have been accumulated at Jefferson Lab with the CLAS spectrometer using 5.7…

High Energy Physics - Experiment · Physics 2010-04-06 S. Chen , H. Avakian , V. Burkert , P. Eugenio , the CLAS collaboration

Neural networks are utilized to fit Compton form factor H to HERMES data on deeply virtual Compton scattering off unpolarized protons. We used this result to predict the beam charge-spin assymetry for muon scattering off proton at the…

High Energy Physics - Phenomenology · Physics 2011-10-20 Kresimir Kumericki , Dieter Mueller , Andreas Schafer

Combining dispersion and operator product expansion techniques, we derive the conformal partial wave decomposition of the virtual Compton scattering amplitude in terms of complex conformal spin to twist-two accuracy. The perturbation theory…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. Kumericki , D. Müller , K. Passek-Kumericki

We present the results of calculations analyzing nucleon Compton scattering to lowest order using perturbative QCD (pQCD) methods. Two scenarios are considered: (1) the incoming photon is real; and (2) the incoming photon is virtual. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 Richard Thomson , Alex Pang , Chueng-Ryong Ji

We present in detail a dispersion relation formalism for virtual Compton scattering (VCS) off the proton from threshold into the $\Delta(1232)$-resonance region. Such a formalism can be used as a tool to extract the generalized…

High Energy Physics - Phenomenology · Physics 2016-09-06 B. Pasquini , M. Gorchtein , D. Drechsel , A. Metz , M. Vanderhaeghen

A factorized Regge-pole model for deeply virtual Compton scattering is suggested. The use of an effective logarithmic Regge-Pomeron trajectory provides for the description of both ``soft'' (small $|t|$) and ``hard'' (large $|t|$) dynamics.…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Capua , S. Fazio , R. Fiore , L. Jenkovszky , F. Paccanoni

In recent years, real and virtual Compton scattering off the nucleon have attracted considerable interest from both the experimental and theoretical sides. Real Compton scattering gives access to the so-called electromagnetic…

Nuclear Theory · Physics 2009-11-10 Stefan Scherer

We give an overview of low-energy Compton scattering (gamma^(*) p --> gamma p) with a real or virtual incoming photon. These processes allow the investigation of one of the fundamental properties of the nucleon, i.e. how its internal…

Nuclear Experiment · Physics 2011-09-23 E. J. Downie , H. Fonvieille

We study the double deeply virtual Compton scattering (DDVCS) process off the nucleon, through the scattering of a spacelike virtual photon with large virtuality resulting in the production of a timelike virtual photon, decaying into an e^+…

High Energy Physics - Phenomenology · Physics 2016-09-06 M. Guidal , M. Vanderhaeghen

These lectures give a pedagogical introduction to real and virtual Compton scattering at low energies. We will first discuss real Compton scattering off a point particle as well as a composite system in the framework of nonrelativistic…

Nuclear Theory · Physics 2011-04-15 S. Scherer

Virtual Compton Scattering off the proton: gamma* p to gamma p, is a new field of investigation of nucleon structure. Several dedicated experiments have been performed at low c.m. energy and various momentum transfers, yielding specific…

High Energy Physics - Experiment · Physics 2019-08-15 Helene Fonvieille

We give a complete representation of virtual Compton scattering $\gamma^* p \to \gamma p$ at large initial photon virtuality $Q^2$ and small momentum transfer squared $t$ in terms of the light-cone wavefunctions of the target proton. We…

High Energy Physics - Phenomenology · Physics 2009-09-11 Stanley J. Brodsky , Markus Diehl , Dae Sung Hwang

We investigate the spin-independent part of the virtual Compton scattering (VCS) amplitude off the nucleon within the framework of chiral perturbation theory. We perform a consistent calculation to third order in external momenta according…

Nuclear Theory · Physics 2009-10-30 Thomas R. Hemmert , Barry R. Holstein , Germar Knoechlein , Stefan Scherer

The study of exclusive processes in the future electron-ion ($eA$) colliders will be an important tool to investigate the QCD dynamics at high energies as they are in general driven by the gluon content of the target which is strongly…

High Energy Physics - Phenomenology · Physics 2015-06-11 V. P. Goncalves , D. S. Pires

Double deeply virtual Compton scattering (DDVCS) is the process where an electron scatters off a nucleon and produces a lepton pair. The main advantage of this process in contrast with deeply virtual and timelike Compton scatterings (DVCS…

High Energy Physics - Phenomenology · Physics 2023-05-09 K. Deja , V. Martinez-Fernandez , B. Pire , P. Sznajder , J. Wagner

We study Compton scattering in systems with A=1 and 2 using chiral perturbation theory up to fourth order. For the proton we fit the two undetermined parameters in the O(Q^4) $\gamma$p amplitude of McGovern to experimental data in the…

Nuclear Theory · Physics 2009-04-17 S. R. Beane , M. Malheiro , J. A. McGovern , D. R. Phillips , U. van Kolck

We propose measurements of the deeply virtual Compton amplitude (DVCS), gamma* to H H-bar gamma, in the timelike t = (p_{H} + p_{H-bar})^2 > 0 kinematic domain which is accessible at electron-positron colliders via the radiative…

High Energy Physics - Phenomenology · Physics 2010-03-04 Andrei Afanasev , Stanley J. Brodsky , Carl E. Carlson , Asmita Mukherjee