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We study towers of light particles that appear in infinite-distance limits of moduli spaces of 9-dimensional 𝒩=1 string theories, some of which notably feature decompactification limits with running string coupling. The lightest tower in such decompactification limits consists of the non-BPS Kaluza-Klein modes of Type I′ string theory, whose masses depend nontrivially on the moduli of the theory. We work out the moduli-dependence by explicit computation, finding that despite the running decompactification the Distance Conjecture remains satisfied with an exponential decay rate ⍺ ≥ 1/√(d-2) in accordance with the sharpened Distance Conjecture. The related sharpened Convex Hull Scalar Weak Gravity Conjecture also passes stringent tests. Our results non-trivially test the Emergent String Conjecture, while highlighting the important subtlety that decompactifcation can lead to a running solution rather than to a higher-dimensional vacuum.
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This content will become publicly available on March 1, 2026
Taxonomy of infinite distance limits
The Emergent String Conjecture constrains the possible types of light towers in infinite-distance limits in quantum gravity moduli spaces. In this paper, we use these constraints to restrict the geometry of the scalar charge-to-mass vectors -∇ log m of the light towers and the analogous vector -∇ log Λ of the species scale. We derive taxonomic rules that these vectors must satisfy in each duality frame. Under certain assumptions, this allows us to classify the ways in which different duality frames can fit together globally in the moduli space in terms of a finite list of polytopes. Many of these polytopes arise in known string theory compactifications, while others suggest either undiscovered corners of the landscape or new swampland constraints.
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- PAR ID:
- 10616746
- Publisher / Repository:
- Springer, SISSA
- Date Published:
- Journal Name:
- Journal of High Energy Physics
- Volume:
- 2025
- Issue:
- 3
- ISSN:
- 1029-8479
- Page Range / eLocation ID:
- 213
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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