arXiv subjects

Yehudi Simon

Publications and source records attributed to Yehudi Simon.

3 recordsLinked to original sources

arXiv2026

Kaluza-Klein Perturbation Theory from Exceptional Field Theory

We develop the perturbation theory of ten and eleven-dimensional supergravities on a large class of Kaluza-Klein backgrounds including familiar AdS examples such as AdS$_5\times S^5$, but also more general manifolds such as black hole geometries. Employing ${\rm E}_{6(6)}$ exceptional field theory with the backgrounds characterized by a generalized Scherk-Schwarz ansatz, we determine the first order field equations for the fluctuations that are gauge invariant under linearized generalized diffeomorphisms. We then present the details of the Higgs mechanism for all fields including spin-2 for the subset of backgrounds in which higher-form gauge fields vanish. We use a recently established machinery based on homotopy transfer that allows one to separate the fields into gauge invariant physical modes and pure gauge unphysical modes to all orders in perturbation theory. Finally, as a first application for backgrounds with higher-form gauge fields switched on, we analyze part of the spectrum of ten-dimensional Kaluza-Klein modes of type IIB supergravity around a Kerr-Newman AdS$_5$ black hole that in the near horizon limit becomes a fibered product of AdS$_2$ and a squashed three-sphere.

hep-th↗

arXiv2026

Homotopy transfer for massive Kaluza-Klein modes

We develop techniques to treat massive Kaluza-Klein modes to arbitrary order in perturbation theory. The Higgs mechanism that renders the higher Kaluza-Klein modes massive is displayed. To this end we give an algorithm in perturbation theory that yields new fields with the following characteristics: they are gauge invariant under all higher-mode gauge transformations, which are broken, but they transform covariantly under the zero-mode gauge transformations, which are unbroken. We employ the formulation of field theory in terms of $L_{\infty}$ algebras together with their homotopy transfer, which here maps the gauge redundant fields of gravity to gauge invariant fields. We illustrate these results, as a proof of concept, for Kaluza-Klein theory on a torus. In an accompanying paper these results will be applied to a large class of generalized Scherk-Schwarz backgrounds in exceptional field theory.

hep-th↗

arXiv2023

Precision predictions for exotic lepton production at the Large Hadron Collider

We calculate total and differential cross sections for the pair production, at the Large Hadron Collider, of exotic leptons that could emerge from models with vector-like leptons and in Type-III seesaw scenarios. Our predictions include next-to-leading-order QCD corrections, and we subsequently match them with either parton showers, or threshold resummation at the next-to-next-to-leading logarithmic accuracy. Our results show an important increase of the cross sections relative to the leading-order predictions, exhibit a distortion of the shapes for various differential distributions, and feature a significant reduction of the scale uncertainties. Our predictions have been obtained from new FeynRules model implementations and associated UFO model libraries. This completes the set of next-to-leading-order implementations of new physics models featuring extra leptons that are publicly available on the FeynRules model database.

hep-ph↗