Light scalar from deformations of the Klebanov-Strassler background

Understand

We study deformations of the Klebanov-Strassler background parametrized by the size of a dim-6 VEV.

• In the UV, these solutions describe the usual duality cascade of Klebanov-Strassler; however below the scale rho* set by the dim-6 VEV they exhibit hyperscaling violation over a range of the radial coordinate.
• Focusing on the spectrum of scalar glueballs, we find a parametrically light state, the mass of which is suppressed by rho*, becoming massless in the limit of rho* -> infinity.
• Along the way, we clarify the choice of IR and UV boundary conditions for the fluctuations in the bulk, and find agreement with previous calculations for the spectrum of Klebanov-Strassler.