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Searching for the N-naturalness tower of neutrinos

Sofia Lonardi1,*, Manuel Ettengruber2,†, and Philipp Eller3,‡

  • *Contact author: sofia.lonardi@physik.uni-freiburg.de
  • †Contact author: manuel-meinrad.ettengruber@ipht.fr
  • ‡Contact author: philipp.eller@tum.de
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Phys. Rev. D 114, 075022 – Published 14 October, 2026

DOI: https://doi.org/10.1103/yhpw-px34

Abstract

We present the first experimental search for the N-naturalness tower of neutrinos using a global analysis of publicly available neutrino data. As a potential solution to the hierarchy problem, the N-naturalness model employs a varying Higgs mass parameter among N dark sectors and encodes the required fine-tuning of the placement of the sectors in a parameter r. We report exclusion limits on the parameter space (r, N), for normal and inverted ordering and in case the neutrino is Majorana or Dirac. In the case of a Majorana neutrino, we can rule out N≤104 sectors with r≥0.1. This is particularly exciting as it shows that a gauge and gravitational unification around MGUT, which is a benchmark scenario of the N-naturalness framework with N=104 without fine-tuning, is ruled out by neutrino experiments.

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Phys. Rev. D 114, 075022– Published 14 October, 2026
  • Received 16 July 2026
  • Accepted 28 September 2026
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