Electromagnetic and gravitational form factors in simulated QED and   Yukawa model
  The light-cone Fock state representation of composite systems has number of remarkable properties and for systems such as hadrons they have exact representation for angular momentum, energy momentum tensor. We investigate the electromagnetic and gravitational form factors with zero momentum transfer in QED and Yukawa theory. To improve the convergence near the end points of $x$ qualitatively as well as to check the consistency of the model, we differentiate the wavefunction w.r.t. bound state mass. We test the behaviour of the anomalous gravitomagnetic moment, which follows directly from the Lorentz boost properties of the light-cone Fock representation, for the simulated model as well as the Yukawa model. We also discuss the Pauli form factor obtained from the spin-flip matrix element. 
Narinder Kumar and Harleen Dahiya
hep-ph