A Custodial Symmetry for Muon g-2

In this talk I would discuss the recent results on the muon anomalous magnetic moment in the context of new physics models with light scalars. I would present a model in which the one-loop contributions to g-2 of a scalar and a pseudoscalar naturally cancel in the massless limit due to the symmetry structure of the model. This model allows to interpolate between two possible interpretations. In the first interpretation, the results provide a strong evidence of the existence of new physics, dominated by the positive contribution of a CP-even scalar. In the second one, supported by the recent lattice result, the data provides a strong upper bound on new physics, specifically in the case of (negative) pseudoscalar contributions. Finally, I would present an overview on future tree-level searches for muon forces carriers, including a new proposal based on the planned FASER experiment the LHC.

Note the seminar is in-person - but will also be streamed on Zoom - the link will be sent in a separate email.