Mesons as Open Strings in a Holographic Dual of QCD

We study meson spectrum obtained from massive open string modes in a holographic dual of QCD constructed on the basis of a D4/D8-brane configuration in type IIA string theory. The spectrum includes mesons with spin higher than one. Taking into account the effect of curved background perturbatively, we obtain a mass formula for these mesons. The mass formula exhibits the linear Regge behavior at the leading order with subleading non-linear corrections. We argue that the string spectrum captures some features of the observed meson spectrum. For example, a(2)(1320), b(1)(1235), pi(1300), a(0)(1450), etc., are identified as the first excited massive open string states and rho(3)(1690), pi(2)(1670), etc., are identified as the second excited states.