The scientific focus of PheNUmenal followed two main paths. On one hand, it delved into the theoretical aspects of the SMEFT extension to include sterile neutrinos, the vSMEFT. In particular, the project explored the role of neutrino Yukawa couplings, which had largely been overlooked in previous vSMEFT studies, and computed the complete set of one-loop renormalization group evolution (RGE) equations of the theory, complementing and extending existing partial results.
On the other hand, PheNUmenal investigated a wide range of phenomenological implications related to neutrinos and effective field theories (EFTs). Considering the existence of heavy neutrinos, the project examined their impact on low-energy observables, conducting a global analysis to establish general constraints on their existence. It also explored their potential signals at high-energy colliders, such as the LHC. Regarding EFTs, PheNUmenal investigated rare processes forbidden in the Standard Model (SM), setting model-independent constraints on processes involving the emission of two photons. More broadly, it carried out the first global analysis of the lepton flavor violating (LFV) sector of the SMEFT. By integrating both neutrino and EFT frameworks, PheNUmenal analyzed the impact of incorporating bounds from neutrino non-standard interactions (NSI) into the global SMEFT framework, as well as deriving bounds for LFV vSMEFT operators due to the RGE effects from their Yukawa interactions.
Additionally, in parallel with its main objectives, PheNUmenal also examined the role of massive neutrinos in cosmology. This investigation was motivated by recent findings from the DESI collaboration, which set stringent constraints on the absolute neutrino mass scale, presenting a tension with the current understanding from neutrino oscillation experiments. The study offered a critical analysis of the status quo, highlighting the importance of cosmological models, statistical approaches, and the handling of systematics when setting cosmological bounds for neutrino masses.
As a result of this research, PheNUmenal published eight research articles in international journals and presented its findings at eight international conferences and workshops, also publishing two additional proceedings. All these contributions show the deep impact of current experimental facilities in the search of new physics in neutrino and EFT frameworks.
