An EFT Likelihood for Beyond the Standard Model Phenomenology

• Aleks Smolkovic (Jozef Stefan Institute)

Room: 4/2-037 - TH meeting room The Standard Model (SM) remains incomplete, but direct searches for new particles have so far provided no clear evidence of physics beyond it. The SM Effective Field Theory (SMEFT) has proven to be a valuable framework for studying a broad class of models beyond the SM containing heavy degrees of freedom. In particular, the phenomenology of SMEFT can be developed systematically, incorporating essential effects such as Renormalization Group (RG) evolution and matching onto subsequent low-energy effective field theories, ultimately enabling predictions for a wide range of experimentally accessible observables. A likelihood function for the SMEFT that compares theory predictions to experimental data can be employed to identify potential patterns of deviation from SM predictions, but also to study the phenomenology of any specific model that can be matched onto SMEFT. In this talk, I will present a new open-source Python package, jelli (a JAX-based EFT likelihood), which provides an easy-to-use and highly efficient framework for implementing global EFT likelihood functions. I will demonstrate how to use it on examples including flavour physics, electroweak precision observables, and high-mass Drell-Yan tails.