Asymptotic properties of Hulthén model form factors on the light front

Abstract

We use light-front dynamics to calculate the electromagnetic form-factor for the Hulthén model of the deuteron. For small momentum transfer Q 2 < 5 GeV 2 the relativistic effects are quite small. For Q 2 ∼ 11 GeV 2 there is ∼ 13% discrepancy between the relativistic and non-relativistic approaches. For asymptotically large momentum transfer, however, the light-front form factor, ∼ log Q 2 /Q 4 , markedly differs from the non-relativistic version, ∼ 1/Q 4 . This behavior is also present for any wave function, such as those obtained from realistic potential models, which can be represented as a sum of Yukawa functions. Furthermore, the asymptotic behavior is in disagreement with the Drell-Yan-West relation. We investigate precisely how to determine the asymptotic behavior and confront the problem underlying troublesome form factors on the light front.

Generalized vector form factors of the pion in a chiral quark model

“…The pion GPDs were also analyzed in other variants of chiral quark models in Refs. [12,13,14,15,16,17]. In this paper we use the non-linear NJL model with the PV regularization in the twice-subtracted version proposed in Ref.…”

Inequalities for nucleon generalized parton distributions with helicity flip

“…[37,38]. The positivity bounds can be used for self-consistency checks of models of GPDs [39,40,41,42,43,44].…”

Double distributions for the proton

“…The wave function representation of GPDs has another salient feature: the positivity bounds [11,16,17,18,19,20,21] are transparent. Additionally there is the possibility to elucidate the continuity of GPDs in light-cone time-ordered perturbation theory [22]. Despite these virtues, however, little has been done to understand how the reduction properties of GPDs arise within the light-cone wave function representation.…”

“…Overall there is still little insight in constructing DDs with dynamical content. Furthermore, as we pointed out, connection to light-cone wave functions and the intuition of the Fock space expansion is difficult at best [27], except in simple model scenarios [28,29,30].…”