In this talk, I re-visit the original relaxion model by Graham-Kaplan-Rajendran in the regime where the relaxion is subject to large fluctuations during its dynamics. I discuss the modified stopping conditions for such dynamics of the relaxion and the new parameter space. Interestingly, in a significant region of the parameter space, the relaxion can naturally account for the observed dark...
Self-organised criticality, realised through cosmological dynamics in the early universe, is an alternative paradigm for addressing the electroweak hierarchy problem. In this scenario, an unnaturally light Higgs boson is the result of dynamics driving the electroweak vacuum towards a near-critical metastable point where the Higgs mass is bounded from above by the vacuum instability scale. To...
After discussing some history of the hierarchy problem, I recast the hierarchy problem as a legitimate paradox. The premises and reasoning of the paradox are explained. I discuss how each premise has been attacked and what ideas are still standing and which directions are perhaps less interesting today after a generation of experimental and theoretical work.
We study the IR fate of Chiral Gauge Theories through functional methods and the Effective Average Action. Our results show a rich structure, from the existence of IR conformality to new patterns of Chiral Symmetry Breaking.
We carry out a detailed analysis of the region slightly outside the conformal window of a non-trivial infrared fixed point in a generic bottom-up holographic setup. We focus on models, which study the dynamics of a scalar field, dual to quark degrees of freedom, in a (nearly) AdS geometry. Such models realize the picture expected for vector-like near-conformal theories from Dyson-Schwinger...
I will describe a model of hybrid inflation coming from a general composite theory. Starting from an effective chiral Lagrangian with a dilaton and pions, we identify inflation occurring during the walking dynamics of the theory. A Z2 symmetry-breaking term in the pion sector induces a shift in the inflaton’s trajectory, which leads to a tachyonic instability phase. Curvature perturbations...
For pNGB-based approaches, the phenomenological question of Higgs naturalness finds itself at a tipping point between direct searches and precision. As we look ahead to the HL-LHC era and beyond, a scenario in which all measurements remain Standard Model-like would only sharpen the naturalness tension, driven increasingly by precision constraints. To illustrate this from a fresh perspective,...
