Speaker: Carlos Henrique de Lima, Carleton University
Abstract: In this work, we study the status of negative coupling modifiers in extended Higgs sectors, focusing on the ratio of coupling modifiers that probes custodial symmetry violation λWZ=κW/κZ. Higgs sectors with multiplets larger than doublets are the only weakly coupled models that give tree-level modifications to λWZ, and we explore all such models allowed by the constraint from the ρ parameter and perturbative unitarity. This class of models has a custodial symmetry violating potential, while the vacuum configuration preserves the symmetry. We apply precision measurements from ATLAS and CMS and show that each data set can exclude a vast set of models with λWZ<0 at greater than 95\% confidence level. We give evidence that λWZ<0 is excluded in all weakly coupled models.