Positivity bounds in the standard model effective field theory beyond tree level

Focusing on four-Higgs interactions, we analyse the robustness of tree-level-derived positivity bounds Standard Model effective field theory (SMEFT) operators under quantum corrections. Among other results, demonstrate that: (i) Even in simplest extensions Model, e.g. with one new scalar singlet or a neutral triplet, some are strictly violated; (ii) mixing dimension-eight renormalisation, which compute here for first time, can drive them out their region; (iii) running interactions triggered by solely dimension-six terms respects bounds. Our results suggest, hand, that departures from within SMEFT, if ever found data, do not necessarily imply breaking unitarity causality, nor presence light degrees freedom. On they lead to strong constraints form certain anomalous dimensions.