Higgs decays to two leptons and a photon beyond leading order in the SMEFT

Abstract

We present the three-body decay of the Higgs boson into two leptons and a photon to dimension-eight in the Standard Model Effective Field Theory (SMEFT). In order to obtain this result we interfere the full one-loop Standard Model result with the tree-level result in the SMEFT. This is the first calculation of the partial width of the Higgs boson into two leptons and a photon in the SMEFT to incorporate the full one-loop dependence for the Standard Model as well as the full tree level dimension-eight dependence in the SMEFT. We find that this channel can aid in distinguishing strongly interacting and weakly interacting UV completions of the SMEFT under standard assumptions. We also find that this channel presents the opportunity to distinguish different operator Classes within the SMEFT, potentially including contact H ¯ γ operators which are first generated only at dimension-eight in the SMEFT.

Monolepton production in SMEFT to $$ \mathcal{O} $$(1/Λ4) and beyond

“…In this paper we have studied SMEFT corrections to monolepton production at O(1/Λ 4 ), adding it to the list processes [6,[8][9][10]57] now known to that order. We are particularly interested in the relative size of the O(1/Λ 2 ) and O(1/Λ 4 ) pieces and how that changes as we push into the ŝ m 2 W regime.…”

The Impact of Dimension-8 SMEFT Contributions: A Case Study

“…The results of Refs. [14,60] suggest that the dimension-8 contributions may play a more significant role in such scenarios.…”