Gluon gravitational form factors of the nucleon and the pion from lattice QCD

A future electron-ion collider will enable the gluon contributions to the gravitational form factors of the proton to be constrained experimentally for the first time. Here, the first calculation of these form factors from lattice quantum chromodynamics is presented. The calculations use a larger-th...

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Bibliographic Details
Main Authors: Shanahan, Phiala E, Detmold, William
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics
Format: Article
Language:English
Published: American Physical Society 2019
Online Access:http://hdl.handle.net/1721.1/120119
https://orcid.org/0000-0002-0400-8363
Description
Summary:A future electron-ion collider will enable the gluon contributions to the gravitational form factors of the proton to be constrained experimentally for the first time. Here, the first calculation of these form factors from lattice quantum chromodynamics is presented. The calculations use a larger-than-physical value of the light quark mass corresponding to m[subscript π]∼450  MeV. All three form factors, which encode the momentum dependence of the lowest moment of the spin-independent gluon generalized parton distributions and are related to different components of the energy-momentum tensor, are resolved. In particular, the gluon D-term form factor, related to the pressure distribution inside the nucleon, is determined for the first time. The gluon contributions to the two gravitational form factors of the pion are also determined, and are compared to existing lattice determinations of the quark contributions to the gravitational form factors and to phenomenology.