Naturalness vs UV/IR Mixing by Classicalization

by Dr Florian NORTIER (CNRS/IN2P3 - IP2I Lyon)

Thursday 29 Oct 2026, 13:30 → 14:30 Europe/Zurich

4/2-037 - TH meeting room (CERN)

The electroweak hierarchy problem has been a primary motivation for beyond-the-Standard-Model physics over the past four decades. However, the LHC's failure to discover the typical new weak-scale particles predicted by traditional symmetry-based models has placed naturalness under stress. In this talk, I will discuss how a field-theoretical UV/IR mixing, inspired by gravity, can explain the observed hierarchy gap. This scenario relies on UV completion via classicalization, in which a non-localizable scalar theory with Vainshtein screening around energy-momentum sources self-completes by producing extended, semi-classical objects (classicalons) while briefly transitioning through a strong-coupling scale. The key point is that this mechanism requires a little hierarchy between the scalar mass and the strong-coupling scale. The talk will focus on a toy scalar model without gauge interactions, with the inclusion of fermions discussed at the end.