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Sequestering in String Compactifications

Marcus Berg, David Marsh, Liam McAllister, Enrico Pajer

TL;DR

The work investigates whether sequestering of supersymmetry breaking survives in string compactifications where Kahler moduli are stabilized nonperturbatively. It shows that geometric isolation, even with strong warping, does not guarantee sequestering because nonperturbative superpotentials induce cross-couplings between hidden and visible sectors, leading to soft terms that can be sizable and flavor-sensitive. In KKLT scenarios, sfermion masses remain largely flavor-diagonal and suppressed, but μ and Bμ terms receive nontrivial corrections, while in the Large Volume Scenario A-terms can be significantly enhanced, risking flavor violation; thus sequestering requires an additional mechanism to suppress these cross-couplings. Overall, the paper sharpens the criteria for sequestered SUSY breaking by highlighting the crucial role of nonperturbative moduli stabilization in determining the visible-sector soft terms, and it points to the need for explicit model-building that combines sequestering with controlled nonperturbative contributions.

Abstract

We study the mediation of supersymmetry breaking in string compactifications whose moduli are stabilized by nonperturbative effects. We begin with a critical review of arguments for sequestering in supergravity and in string theory. We then show that geometric isolation, even in a highly warped space, is insufficient to achieve sequestering: in type IIB compactifications, nonperturbative superpotentials involving the Kahler moduli introduce cross-couplings between well-separated visible and hidden sectors. The scale of the resulting soft terms depends on the moduli stabilization scenario. In the Large Volume Scenario, nonperturbative superpotential contributions to the soft trilinear $A$ terms can introduce significant flavor violation, while in KKLT compactifications their effects are negligible. In both cases, the contributions to the $μ$ and $Bμ$ parameters cannot be ignored in general. We conclude that sequestered supersymmetry breaking is possible in nonperturbatively-stabilized compactifications only if a mechanism in addition to bulk locality suppresses superpotential cross-couplings.

Sequestering in String Compactifications

TL;DR

The work investigates whether sequestering of supersymmetry breaking survives in string compactifications where Kahler moduli are stabilized nonperturbatively. It shows that geometric isolation, even with strong warping, does not guarantee sequestering because nonperturbative superpotentials induce cross-couplings between hidden and visible sectors, leading to soft terms that can be sizable and flavor-sensitive. In KKLT scenarios, sfermion masses remain largely flavor-diagonal and suppressed, but μ and Bμ terms receive nontrivial corrections, while in the Large Volume Scenario A-terms can be significantly enhanced, risking flavor violation; thus sequestering requires an additional mechanism to suppress these cross-couplings. Overall, the paper sharpens the criteria for sequestered SUSY breaking by highlighting the crucial role of nonperturbative moduli stabilization in determining the visible-sector soft terms, and it points to the need for explicit model-building that combines sequestering with controlled nonperturbative contributions.

Abstract

We study the mediation of supersymmetry breaking in string compactifications whose moduli are stabilized by nonperturbative effects. We begin with a critical review of arguments for sequestering in supergravity and in string theory. We then show that geometric isolation, even in a highly warped space, is insufficient to achieve sequestering: in type IIB compactifications, nonperturbative superpotentials involving the Kahler moduli introduce cross-couplings between well-separated visible and hidden sectors. The scale of the resulting soft terms depends on the moduli stabilization scenario. In the Large Volume Scenario, nonperturbative superpotential contributions to the soft trilinear terms can introduce significant flavor violation, while in KKLT compactifications their effects are negligible. In both cases, the contributions to the and parameters cannot be ignored in general. We conclude that sequestered supersymmetry breaking is possible in nonperturbatively-stabilized compactifications only if a mechanism in addition to bulk locality suppresses superpotential cross-couplings.

Paper Structure

This paper contains 39 sections, 126 equations, 1 figure.

Table of Contents

  1. Introduction
  2. Sequestering in Supergravity and String Theory
  3. Sequestering from barren extra dimensions
  4. Corrections from moduli-mediated interactions
  5. Sequestering in warped compactifications
  6. Warped sequestering in the Klebanov-Strassler throat
  7. Sort-of sequestering
  8. Superpotential de-sequestering
  9. The Effects of Moduli Stabilization: A Toy Model
  10. Supersymmetric vacuum for a D3-brane
  11. The KKLT scenario
  12. Supersymmetric D3-branes in the conifold
  13. Soft masses for the D3-brane
  14. Evaluated soft masses
  15. Lessons from the toy model
  16. ...and 24 more sections

Figures (1)

  • Figure 1: D7-branes on the left of cylinder (in red), D3-branes on the right of cylinder (in blue). Left panel: Five-point function analogous to the two-point function considered in Berg:2004ek. Right panel: the factorized limit. The flavor structure of $\lambda_{ij}^{u}$ may in principle be determined by that of the tree-level (disk) three-point function.