The Precision Frontier plays a unique role in the quest for physics beyond the Standard Model, through precision measurements and searches for rare processes in low energy phenomena.  Within this vibrant research area, this INT program focused on three main thrusts: beta decays of mesons, neutron, nuclei; neutrino-less double beta decay; permanent electric dipole moments of systems ranging from the neutron to atoms and molecules.  The program brought together the various theoretical communities and methodologies interfacing at the precision frontier, that include phenomenology, effective field theory, lattice QCD, and nuclear structure. The objectives of the programs were: (1) discuss the state-of-the-art and identify current gaps in the theoretical treatment of key observables; (2) discuss strategies to address open problems, such as nuclear structure dependent radiative corrections to beta decay; (3) provide a venue where different theoretical communities adequately interface; (4) provide a venue for interaction between the theoretical and experimental communities. These objectives were broadly achieved, as documented by the online presentations.   

Discussions initiated during the program have generated several ideas for follow-up initiatives, which will be pursued by the community in the near future. We mention two examples. First, during the 2^nd week of the program, several workshop participants reiterated the need of a coordinated theoretical and experimental effort for the extraction of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing parameter V_ud from nuclear decays, which is a key input to test the unitarity of the CKM matrix.  Steps towards the formation of a ‘VUDU’ (V_ud Unitarity) working group will follow, possibly aided by a future INT workshop. Similarly, discussions during the 4^th week of the program have highlighted the importance of exploring a renormalized approach to chiral Effective Field Theory (EFT), which may lead to greater control of the theoretical uncertainties associated with cutoff dependence & convergence of the EFT expansion.  These discussions generated a proposal for a future INT workshop on this topic.

INT 23-1b Program Webpage