Abstract
The issue of the contribution of zero-modes to the light-front projection of the electromagnetic current of phenomenological models of vector particles vertices is addressed in the Drell–Yan frame. Our analytical model of the Bethe–Salpeter amplitude of a spin-1 fermion–antifermion composite state gives a physically motivated light-front wave function symmetric by the exchange of the fermion and antifermion, as in the ρ-meson case. We found that among the four independent matrix elements of the plus component in the light-front helicity basis only the 0→0 one carries zero-mode contributions. Our derivation generalizes to symmetric models, important for applications, the above conclusion found for a simplified non-symmetrical form of the spin-1 Bethe–Salpeter amplitude with photon–fermion point-like coupling and also for a smeared fermion–photon vertex model.
Highlights
The issue of the contribution of zero-modes to the light-front projection of the electromagnetic current of phenomenological models of vector particles vertices is addressed in the Drell-Yan frame
We show analytically that zero-mode contributions appearing in the matrix elements of the spin-1 electromagnetic current are canceled in the computation of form factors with the prescription suggested by Ref. [27]
We compute: i) the direct term with γμ vertices from the initial and final states of the vector particle; ii) the cross term with γμ and derivative coupling; iii) the direct term with two derivative couplings. This strategy simplifies the separation of zero-mode contributions present in the different terms of the matrix elements of the electromagnetic current and electromagnetic form factors of the composite vector state
Summary
The issue of the contribution of zero-modes to the light-front projection of the electromagnetic current of phenomenological models of vector particles vertices is addressed in the Drell-Yan frame. We show analytically that zero-mode contributions appearing in the matrix elements of the spin-1 electromagnetic current are canceled in the computation of form factors with the prescription suggested by Ref.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have