Welcome and introduction Room: web/Amphi Dirac

Phenomenology with trans-Planckian asymptotic safety

• Kamila Kowalska

Room: web/Amphi Dirac I will discuss some of the phenomenological aspects of embedding the Standard Model and/or models of New Physics in the framework of trans-Planckian asymptotic safety. In this setting, the presence of an interactive UV fixed point in the renormalization group flow of the gauge and Yukawa couplings imposes boundary conditions at the Planck scale. In the case of New Physics models, the ensuing fixed-point analysis leads to specific predictions for the IR phenomenology. This heuristic approach relies on simplifying approximations, including the computation of renormalization group equations at 1-loop, an arbitrary definition of the position of the Planck scale, and instantaneous decoupling of gravity. I will discuss how robust the predictions from asymptotic safety are if the assumptions listed above are relaxed.

Naturally small neutrino mass from asymptotic safety

• Enrico Sessolo

Room: web/Amphi Dirac I will discuss the possibility of dynamically generating arbitrarily small Yukawa couplings in the framework of trans-Planckian asymptotic safety. This effective mechanism may provide an interesting alternative to other dynamical means to generate small neutrino masses, e.g., the see-saw mechanism, and can be applied to various new physics scenarios requiring feeble Yukawa interactions (freeze-in dark matter, etc). I will show that this mechanism can be consistent with first-principle calculations in quantum gravity using the functional renormalization group. Finally, I will discuss possible gravitational-wave signals arising from the connection between these extreme UV and IR sectors.

(Remote) On the many natures of the Higgs: From Composite Higgs Dynamics to the Standard Model as Magnetic Theory

• Francesco Sannino

Room: web/Amphi Dirac

UV-Completion Beyond Asymptotic Safety: Vainshtein Screening, UV/IR Mixing & Electroweak Naturalness

• Florian NORTIER (CNRS/IN2P3 - IP2I Lyon)

Room: web/Amphi Dirac If one could probe sub-Planckian length scales by a hard (UV) scattering experiment, one would expect to end up with an extended semi-classical state (black hole) that decays into many soft (IR) quanta by Hawking radiation. This UV/IR mixing in gravity (dubbed classicalization) is a deeply nonlocal phenomenon. It suggests a path towards UV-completion by UV-obstruction, different from the traditional Wilsonian UV-fixed point (asymptotic safety). If the Standard Model is extended by specific self-sourced operators, the electroweak scale could also be stabilized against new large scales via Vainshtein screening that requires a little hierarchy. In this talk, I will discuss that implementing a ghost-free nonlocal Higgs mechanism leads to classicalization of the Higgs field, suggesting that fuzzy interactions trigger classicalization. References: arXiv:1010.1415, arXiv:2307.11741, arXiv:2311.08311

Dualities in the UV

• Borut Bajc

Room: web/Amphi Dirac

Asymptotic Grand Unification in 5 dimensions

• Giacomo Cacciapaglia (IP2I Lyon)

Room: web/Amphi Dirac

Orbifold Stability of Asymptotic GUTs

• Anca Preda

Room: web/Amphi Dirac

Directions for Model Building beyond Asymptotic Freedom

• Daniel Litim (University of Sussex)

Room: web/Amphi Dirac It is widely appreciated that the Standard Model is incomplete. Yet, and despite of significant experimental efforts, clear-cut signatures for new physics are unavailable. Also, theory guidance beyond the paradigms of asymptotic freedom or effective theories is scarce. In this talk, I discuss top-down and bottom-up directions for model building. From a bottom-up perspective, it is proposed to turn the quest for vacuum stability into a primary model building task. The rationale for this is that while the onset of the SM instability around $10^{11}$ GeV is a high energy effect, a solution may arise from any scale below the Planck scale. Using the renormalisation group, I explain perturbative mechanisms for stability and sketch out the landscape of Planck-safe models. From a top-down angle, prospects for asymptotically safe UV completions of the SM are discussed. Concrete model building results and challenges are highlighted in the context of supersymmetry and UV-safe extensions of the MSSM.

Musings on horizontal gauge symmetries

• Luc Darme

Room: web/Amphi Dirac

Interplay of chiral transitions in the standard model

• Richard Schmieden

Room: web/Amphi Dirac We investigate nonperturbative aspects of the interplay of chiral transitions in the standard model in the course of the renormalization flow. We focus on the chiral symmetry breaking mechanisms provided by the QCD and the electroweak sectors, the latter of which we model by a Higgs-top-bottom Yukawa theory. The interplay becomes quantitatively accessible by accounting for the fluctuation-induced mixing of the electroweak Higgs field with the mesonic composite fields of QCD. In fact, our approach uses dynamical bosonization and treats these scalar fields on the same footing. In the first project we look at the changed infrared behaviour of the theory under inclusion of the QCD sector, compared to the pure Higgs-top-bottom model, with a focus on studying the naturalness problem in the model. In the current project we investigate UV completions within the Higgs-QCD model, a first analysis shows the existence of CEL-like scaling solutions.

Safety, Criticality and Large N

• Shahram Vatani (GGI Firenze)

Room: web/Amphi Dirac I will discuss new RG relations obtained from studying the critical exponent in d dimension. As an example, I will apply those results to the Large Nf paradigm before discussing higher order corrections.