Pion gravitational form factors at large momentum transfer in the instant-form relativistic impulse approximation approach

Abstract

We extend our relativistic theory of gravitational structure of composite hadrons to obtain the pion gravitational form factors at large momentum transfers. The approach was used in the case of intermediate region of the variable in our preceding works arXiv:2010.11640 and arXiv:2201.04991. The calculation is carried out in the framework of a relativistic composite-particle model complemented by the special relativistic form of impulse approximation. It is found that in the limit of massless and pointlike quarks, the obtained asymptotic expansion coincides with the predictions of perturbative QCD for gravitational pion form factors. The principal contribution to the asymptotics, coinciding with the predictions of QCD, is given by the relativistic effect of spin rotation. In particular, the asymptotics of the D form factor is completely determined by this kinematic effect. Several constraints on the allowed form of gravitational form factors of quarks are derived.