Logo FlavourFIPs

The feeble interaction frontier of flavour physics

a Marie Skłodowska-Curie Individual Fellowship

Objective

Despite all its successes, the shortcomings of the Standard Model of particle physics are well-known: for instance the origin of its flavour structure, the absence of a dark matter candidate, or the strong CP problem.

While many of the new physics models aiming at solving them rely on new particles around the TeV scale, this is neither a requirement nor the simplest solution in many cases. In fact, new light but Feebly Interacting Particles (FIPs) often represent the most straightforward solution, with deep implications for flavour physics, dark matter, astrophysics and cosmology. As particle physics enters a new era of “precision”, dozens of experiments, ranging from the High Luminosity LHC to neutrinos experiments, will have the potential to search for such particles.

FlavourFIPs aims at exploring the uncharted links between such versatile new physics candidates and the Standard Model flavour problem.

Partners

EU emblem Logo CNRS Logo IP2I

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101028626.

Publications

The axion flavour connection At the hear of the this MSCA-IF research is the idea that light particles may arise from new structures in the UV. This work is the perfect illustration of this mechanism at work. We explored with my collaborators new structures far above the LHC, TeV, scale which can give rise naturally to a extremely light new particle: the so-called QCD axion. This paper represents the first proof-of-principle that the SM flavour structure can be realised while preserving the masslessness of the axion up to operators of dimension 11, ensure that QCD effects dominates in fixing the axion mass and consequently, that it constitutes a true solution to the strong CP problem.
Resonant search for the X17 boson at PADME A second short letter whose underlying direction arose as a by-product of my previous research on FIPs. Leveraging again resonant production, we designed a new research strategy around the PADME experimental apparatus which has the potential to convincingly deciding whether a controversial measurement from the ATOMKI collaboration arises from a new physics particle or not.
Atmospheric resonant production for light dark sectors (Phys.Rev.D 106, 2022) A short letter whose idea arose as a by-product of my previous research on FIPs. The resonant production mode for FIP, used in the paper just below, is shown to be the dominant one in the fascinating environment of atmospheric particle showers. Including it can improve the production for MeV-scale new physics particles up to a hundredfold and opens new experimental directions for kilotons neutrinos detectors.
The muon g-2 anomaly confronts new physics in electrons and muons final states scattering (JHEP 03 - 2022) with Giovanni Grilli di Cortona and Enrico Nardi. Sometimes, a FIP does not have to distinguish between the different flavours in order to create a flavourfull effect. We study in this work how by choosing carefully its mass, a new particle can have a dramatic indirect effect on the muon g-2. This opens a new direction to solve several on-going anomalies in the determination of the most important component of the SM prediction for the muon g-2: the hadronic vacuum polarisation.
Flavour anomalies and the muon g − 2 from feebly interacting particles (JHEP 03 (2022) 085): with Marco Fedele, Kamila Kowalska, and Enrico Sessolo. A first step into the realm of light but flavourful new particles. We perform a phenomenological analysis of simplified models of feebly interacting particles (FIPs) that can provide a combined explanation of the anomalies into semi-leptonic B mesons decay at LHCb and the anomalous magnetic moment of the muon. It turns out that this requires the FIP masses to be above a few GeV, while providing a clear experimental targets for the ATLAS and CMS collaborations.