N=1 SQCD-like theories with N_f massive flavors from AdS/CFT and beta functions

Abstract

We study new supergravity solutions related to large-$N_c$ $\mathcal{N}=1$ supersymmetric gauge field theories with a large number $N_f$ of massive flavors. We use a recently proposed framework based on configurations with $N_c$ color D5 branes and a distribution of $N_f$ flavor D5 branes, governed by a function $N_{f}S(r)$. Although the system admits many solutions, under plausible physical assumptions the relevant solution is uniquely determined for each value of $x\equiv N_f/N_c$. In the IR region, the solution smoothly approaches the deformed Maldacena-Núñez solution. In the UV region it approaches a linear dilaton solution. For $x<2$ the gauge coupling ${\beta }_g$ function computed holographically is negative definite, in the UV approaching the NSVZ $\beta$ function with anomalous dimension ${\gamma }_0=-1/2$ (approaching $-3/(32{\pi }^2)(2N_c-N_f)g^3$)), and with ${\beta }_g\to -\infty$ in the IR. For $x=2$, ${\beta }_g$ has a UV fixed point at strong coupling, suggesting the existence of an IR fixed point at a lower value of the coupling. We argue that the solutions with $x>2$ describe a "Seiberg dual" picture where $N_f-2N_c$ flips sign.

Comments: 18 pages, 10 figures