End-point singularities of Feynman graphs on the light cone

Abstract

We show that some Lorentz components of the Feynman integrals calculated in terms of the light-cone variables may contain end-point singularities which originate from the contribution of the big-circle integral in the complex k_ plane. These singularities appear in various types of diagrams (two-point functions, three-point functions, etc) and provide the covariance of the Feynman integrals on the light-cone. We propose a procedure for calculating Feynman integrals which guarantees that the end-point singularities do not appear in the light-cone representations of the invariant amplitudes.

final version to appear in PLB; few references added

References in corpus (2)

• Electromagnetic form factors in the light-front formalism and the Feynman triangle diagram: spin-0 and spin-1 two-fermion systems
• Comparison among Hamiltonian light-front formalisms at q+ = 0 and q+ <> 0: space-like elastic form factors of pseudoscalar and vector mesons

Cited by in corpus (6)

• Possible evidence of extended objects inside the proton
• Fermionic bound states in Minkowski-space: Light-cone singularities and structure
• Frame dependence of form factors in light-front dynamics
• Possible evidence of extended objects inside the proton
• Longitudinal structure function of the proton at low momentum transfer and extended constituents
• Covariant analysis of electromagnetic current on the light cone: exposition with scalar Yukawa theory