Bound states of purely relativistic nature

- relativistic bound states ∗

We investigate transition form factors between non-relativistic QCD bound states at large recoil energy. Assuming the decaying quark to be much heavier than its decay product, the relativistic dynamics can be treated according to the factorization formula for heavy-to-light form factors obtained from the heavy-quark expansion in QCD. The non-relativistic expansion determines the bound-state wav...

Relativistic Bound States

In this contribution, I will give a brief survey of present techniques to treat the bound state problem in relativistic quantum field theories. In particular, I will discuss the Bethe–Salpeter equation, various quasi–potential equations, the Feynman–Schwinger representation, and similarity transformation methods for Hamiltonian approaches in light–front quantization. Finally, I will comment on ...

Electromagnetic scattering from relativistic bound states.

The quasipotential formalism for elastic scattering from relativistic bound states is formulated based on the instant constraint in the Breit frame. The quasipotential electromagnetic current is derived from Mandelstam's vepoint kernel and obeys a two-body Ward identity. Breit-frame wave functions are obtained directly by solving integral equations with nonzero total threemomentum, thus accompl...

Mesons: Relativistic Bound States with String Tension

A systematic method of analysing Bethe-Salpeter equation using spectral representation for the relativistic bound state wave function is given. This has been explicitly applied in the context of perturbative QCD with string tension in the 1 N expansion. We show that there are only a few stable bound state mesons due to the small ”threshold mass”(constituent mass) of quarks. The asymptotic prope...

Baryons as Relativistic Bound States of Quark and Diquark