Arnab Roy: Dark Sectors at the LHC and beyond: From Monojet Searches to Semi-Visible Higgs Decays

Thursday 26 Nov 2026, 11:00 → 12:00 Europe/Ljubljana

A/1-106 - Seminarska soba fizike (F5) (Jamova)

I will present a Dark-SMEFT perspective on searches for light invisible particles at the LHC and HL-LHC, focusing on two complementary probes: monojet production and semi-visible Higgs decays in associated (ZH) production. While monojet searches often provide strong sensitivity, their interpretation can be affected by the validity of the effective field theory (EFT) at high transverse momenta and by the underlying ultraviolet (UV) completion. I will discuss practical diagnostics of EFT validity through explicit comparisons between EFT and UV-complete descriptions, along with theoretical and experimental constraints on the parameter space. I will then turn to semi-visible Higgs decays, which offer a complementary way to probe dark-SMEFT operators at typically lower momentum transfers, and discuss their prospects at the HL-LHC. Finally, I will highlight how collider kinematic observables can help discriminate between different effective operator structures of the underlying dark sector.