Lattice QCD computation of the color fields for the static hybrid quark-gluon-antiquark system, and microscopic study of the Casimir scaling

The chromoelectric and chromomagnetic fields, created by a static gluon-quark-antiquark system, are computed in quenched SU(3) lattice QCD, in a 24³×48 lattice at β=6.2 and a=0.07261(85)fm. We compute the hybrid Wilson loop with two spatial geometries, one with a U shape and another with an L shape. The particular cases of the two-gluon glueball and quark-antiquark are also studied, and the Casimir scaling is investigated in a microscopic perspective. This microscopic study of the color fields is relevant to understanding the structure of hadrons, in particular, the hybrid excitation of mesons. This also contributes to understanding confinement with flux tubes and to discriminating between the models of fundamental versus adjoint confining strings, analogous to type-II and type-I superconductivity.