Physics (Internal)

Searching for Hidden Dark Sectors at the LHC

This event is part of the HET Seminar Series.

The dark matter may be a remnant of strong dynamics that is accessible via a weakly coupled portal. If the hidden-sector states are produced at the LHC, they would undergo a QCD-like shower yielding a spray of stable invisible dark matter along with unstable states that decay back to the Standard Model. Such “semi-visible” jets arise, for example, when their production and decay are driven by a leptophobic Z' resonance; the resulting signature is characterized by significant missing energy aligned along the direction of one of the jets. These events are vetoed by the current suite of searches employed by the LHC, resulting in low acceptance. We demonstrate that the transverse mass—computed using the final-state jets and the missing energy—provides a powerful discriminator between the signal and the QCD background.