Heavy Hybrids Mesons in NRQCD: Fine and Hyperfine Structure

Abstract

We study a Heavy Hybrid Meson system, which is composed of a heavy quark-antiquark pair and a non-trivial contribution coming from the gluon field. The framework of the study is the strong interaction, described by QCD, in the special case where the mass of the quarks is heavy, and much higher than the energies of the gluonic field, which will let us assume a non-Relativistic case and work with the Schrödinger Equation. At leading order, the potential does not depend on the mass and spin of the quarks, but some corrections related to the fine and hyperfine structure (the study will focus on the second one), will come at 1/𝑚𝑄 order, and we will study them. Finally, we will use the results from the hyperfine structure to find relations between the different masses of states in the same spin multiplet.