Title: Zero mode issue in the minus-minus component calculation of the transition form factors in the light-front dynamics.
Abstract: Among the three forms of Hamiltonian dynamics Dirac proposed in 1949, the light-front dynamics (LFD) has the most kinematical Poincare operators. In particular, the longitudinal boost operator becomes kinematical in the LFD. The LFD has very distinct vacuum properties, leading to its zero-mode issue which complicates calculations. The minus components in the LFD, related to higher-twist terms in the PDF and GPD formulations, have been notoriously difficult to calculate. In this talk, I will discuss the "minus-minus" component of the transition amplitude in the meson to two photon process, and discuss the role light-front zero-modes play. I will show the existence of spurious form factors, and that they cancel when the light-front time-ordered diagrams are summed. I will discuss the implication of this toy calculation for the GPD formulation.
Zoom link to live session: https://uiowa.zoom.us/j/99570315915
UICapture link to recordings: