Metastable vacua and D-branes at the conifold

TL;DR

The paper constructs a D-brane quiver realization of metastable SUSY-breaking vacua closely related to ISS by placing fractional branes at a ${b Z}_3$-orbifold of the conifold, yielding an effective ${N_f=N_c+1}$ SQCD with dynamically generated, small quark masses. A stringy instanton generates the crucial mass term for the extra flavor, while one-loop effects stabilize the masses and lift pseudomoduli, yielding a robust metastable SUSY-breaking vacuum that is long-lived under plausible scale hierarchies ${\Lambda_1\ll \Lambda_3 < M_s^*}$ and ${m<\Lambda_3}$. The authors also provide dual descriptions: a type IIB gravity dual with anti-branes in a warped throat and a Type IIA NS5–D4 brane picture, offering a coherent field-theory–gravity perspective on metastability and R-symmetry breaking. The work advances toward realistic SUSY-breaking model-building by dynamically generating small masses, breaking R-symmetry in the non-supersymmetric vacuum, and illustrating how stringy instantons can underpin nonperturbative mass terms, with implications for mediation and phenomenology.

Abstract

We consider quiver gauge theories arising on D-branes at simple Calabi-Yau singularities (quotients of the conifold). These theories have metastable supersymmetry breaking vacua. The field theoretic mechanism is basically the one exhibited by the examples of Intriligator, Seiberg and Shih in SUSY QCD. In a dual description, the SUSY breaking is captured by the presence of anti-branes. In comparison to our earlier related work, the main improvements of the present construction are that we can reach the free magnetic range of the SUSY QCD theory where the existence of the metastable vacua is on firm footing, and we can see explicitly how the small masses for the quark flavors (necessary to the existence of the SUSY breaking vacua) are dynamically stabilized. One crucial mass term is generated by a stringy instanton. Finally, our models naturally incorporate R-symmetry breaking in the non-supersymmetric vacuum, in a way similar to the examples of Kitano, Ooguri and Ookouchi.

Figures (10)

• Figure 1: The quiver describing the field content of the gauge theory at the tip of the non-chiral $\mathbb{Z}_3$ orbifold. The ranks of the gauge groups can be chosen arbitrarily.
• Figure 2: The quiver of the theory (\ref{['5rank']}).
• Figure 3: The extended quiver describing the interaction between the fractional brane system and a Euclidean D1 brane on node 5, represented by a square. The relevant coupling is a quartic one, involving $\alpha,\beta, X_{34}$ and $X_{43}$, (\ref{['instac']}).
• Figure 4: Type IIA configuration for the electric theory with $\langle {M}_{22}\rangle=m=0$.
• Figure 5: Type IIA configuration for the magnetic theory.