アイテム詳細

要旨

Extended scalar sectors and the spontaneous breaking of symmetries form the baseline of many theories beyond the standard model to explain, e.g., neutrino masses, dark matter or baryogenesis. An assumption almost ubiquitous in all literature is the neutrality of the vacuum and the conservation of electric charge. We provide a new perspective on this assumption, which, although experimentally well-founded, is not a theoretical necessity. General scalars that obtain vacuum expectation values in their charged components are considered, and we will see how they bring about corrections to the gauge boson masses, the weak mixing angle, expected fermion and boson charges, and many more. We develop a framework to sensibly talk about electric charge in the broken phase and apply it to the case of minicharged particles. Scalars with special representations under the standard model gauge group that allow for new interactions are examined, and we show how they lead to the mixing of charged and uncharged leptons. To this end, we introduce a new basis with corresponding Feynman rules and demonstrate their application with a few examples. Throughout this discussion, we relate our results to the latest experimental limits and give general bounds on parameters and observables.