On the spectrum of open strings in the Hard-Wall model of AdS/QCD: the role of $S^5$

Abstract

We revisit the problem of a classical open string representing a meson in the hard-wall geometry and consider the $S^5$ compact space. The existence of a confining region leads to a discrete set of string configurations parameterized by the number $n$ of complete turnarounds $S^5$ great circles. Unlike the conformal case, the string in the bulk can explore $S^5$ even in the case of equal boundary conditions on its endpoints. The string solutions are parameterized by an internal dimensionless conserved charge $l_n$. The $q\bar{q}$ potential is linear for large separations, and the string tension is sensitive to $l_n$.

Comments: 7 pages; 2 figures