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Novel bounds from the weak gravity and Festina-Lente conjectures

Fayez Abu-Ajamieh1,*, Pratik Chattopadhyay2,†, Nobuchika Okada3,‡, Roman Pasechnik4,§, and Zhi-Wei Wang2,∥

  • *Contact author: fayezabuajamieh@gmail.com
  • †Contact author: pratikpc@gmail.com
  • ‡Contact author: okadan@ua.edu
  • §Contact author: roman.pasechnik@fysik.lu.se
  • ∥Contact author: zhiwei.wang@uestc.edu.cn
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Phys. Rev. D 113, 035039 – Published 27 February, 2026

DOI: https://doi.org/10.1103/fxm9-6dx9

Abstract

We demonstrate that the weak gravity conjecture (WGC) and the Festina-Lente conjecture (FLC) yield novel bounds on any hypothetical fifth force and millicharged particles (mCPs), as well as on the scale of inflation and on the effective Higgs quartic interaction. In particular, we find that combining the FLC with inflation leads to stronger bounds on mCPs than what the simple application of the FLC provides. Furthermore, we have explored the implications of naturalness on both the FLC and WGC, and have found that these conjectures place a lower limit on the charge of a U(1) gauge group.

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Phys. Rev. D 113, 035039– Published 27 February, 2026
  • Received 26 September 2025
  • Accepted 20 January 2026
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