Drag Force in the Vacuum of Confining Gauge Theories

TL;DR

This paper uses gauge/gravity duality to show that in certain confining gauge theories, an isolated quark experiences a vacuum drag force, linking confinement phenomena to resistance against quark propagation.

Contribution

It demonstrates that a holographic dual geometry induces a vacuum drag force on an isolated quark, connecting confinement and vacuum resistance in non-conformal gauge theories.

Findings

A drag force exists for quarks in the vacuum in certain gauge theories.

The presence of a linear $q\bar{q}$ potential correlates with vacuum drag force.

Holography reveals confinement-related phenomena as vacuum resistance.

Abstract

The complete absence of isolated quarks reaching particle detectors after high energy collisions suggests that some physical mechanism generates resistance to their propagation in the vacuum. In order to reveal such a mechanism, we analyze the fate of an infinitely heavy quark that is initially propagating in the vacuum with inertial motion. The non-perturbative structure of the vacuum is treated here using the gauge/ gravity correspondence, the isolated quark on the boundary gauge theory is dual to a trailing string moving in the bulk of a higher dimensional curved space. We find that, for a large class of non-conformal gauge theories with a holographic dual, the geometrical structure of the bulk geometry induces a drag force on the quark that moves in the vacuum. In addition, we show that for these gauge theories there will be the presence of such a drag force due to its vacuum whenever the dual bulk geometry generates a linear potential for a $q\bar{q}$ pair. The relation of the linear $q\bar{q}$ potential with the drag force on the isolated quark is a holographic piece of evidence that both phenomena are different manifestations of the confinement of quarks.