Drag force in the vacuum of confining gauge theories

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 q over bar pair. The relation of the linear q q over bar 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. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.

Automated summary

The absence of isolated quarks reaching particle detectors after high energy collisions suggests a physical mechanism that resists their propagation in the vacuum. In this study, the fate of an infinitely heavy quark initially propagating in the vacuum with inertial motion is analyzed. The non-perturbative structure of the vacuum is treated using the gauge/gravity correspondence, and it is found that the bulk geometry induces a drag force on the quark in the vacuum for certain non-conformal gauge theories with a holographic dual. Additionally, the presence of a linear potential for a qq over bar pair in the dual bulk geometry is shown to be related to the drag force on the isolated quark, providing evidence for the confinement of quarks.