N=1 Matter from Fractional Branes

TL;DR

This paper investigates a specific bound state of fractional D-branes in string theory, deriving the gauge theory spectrum, boundary actions, and supergravity solutions, and confirming anomaly cancellation.

Contribution

It provides a detailed analysis of fractional D3- and D7-brane bound states, including the open string spectrum, boundary actions, and supergravity solutions with anomaly matching.

Findings

Derived the open string spectrum for the bound state.

Computed the boundary action of D7-branes on the orbifold.

Reproduced gauge theory anomalies from supergravity solutions.

Abstract

We study a bound state of fractional D3-branes localized inside the world-volume of fractional D7-branes on the orbifold C^3/Z_2 x Z_2. We determine the open string spectrum that leads to N=1 U(N1)xU(N2)xU(N3)xU(N4) gauge theory with matter having the number of D7-branes as a flavor index. We derive the linearized boundary action of the D7-brane on this orbifold using the boundary state formalism and we discuss the tadpole cancellation. After computing the asymptotic expression of the supergravity solution the anomalies of the gauge theory are reproduced.