Speaker
Bastian Brandt
(U)
Description
Simulations in lattice gauge theory suggest that the formation
of a flux tube between a quark and antiquark leads to quark
confinement. It is conjectured that the infrared behaviour
of the flux tube is governed by an effective string theory
and simulations show good agreement between lattice data and
its predictions. To next-to leading order (R^{-3}) in the inverse
\bar{q}q separation (R) the effective string theory is equivalent
to Nambu-Goto string theory. For the open flux tube in three
dimensions corrections to Nambu-Goto appear at order R^{-4}. They correspond to boundary terms in the worldsheet field theory. These corrections are presumably small for the ground state, but significantly larger for the excited states and lift the degeneracies of the free theory. We compare these predictions to measurements of the
excitation spectrum of the flux tube in 3d SU(2) and SU(3) pure gauge
theory and extract the coefficient of the leading order boundary
term in the effective action.
Author
Bastian Brandt
(U)
