Ronald James Talbert Jr. (Cambridge): An MCMC Revision of the Universal Texture Zero of Flavor

In this talk I plan to address an old problem of particle physics (the flavor puzzle) with an aging solution (a broken non-Abelian discrete symmetry), albeit with a rather novel phenomenological technique: a simple Markov Chain Monte Carlo (MCMC) algorithm. Indeed, the 'Universal Texture Zero' (UTZ) effective theory I co-authored in 2017 was argued to successfully resolve the mass, mixing, and CP-violating structure of both the quark and lepton flavor sectors of the Standard Model with as few as nine infrared model parameters, and in a manner consistent with ultraviolet Grand Unification. However, the original 2017 numerical analysis was insufficient to exhaustively explore even this minimal parameter space, much less that of the augmented next-to-leading order (NLO) UTZ effective Lagrangian, and was not capable (e.g.) of making robust predictions for the leptonic Dirac CP-violating phase, which has yet to be reliably constrained by neutrino oscillation experiments. In our updated analysis we achieve robust predictions for all Dirac and Majorana flavor parameters, permitting an unambiguous route to falsification of the model given improved experimental data, and also demonstrate that the nine-parameter LO UTZ is capable of successful phenomenology without relying on NLO corrections, a welcome conclusion that corrects our findings from 2017. The success of our MCMC approach lends further support to the idea that flavor can be explained dynamically,and represents an early step in the improved analysis of flavored sectors within and beyond the Standard Model. This is relevant not just for model building, but also EFT-based model-independent analyses.