Search for type-III seesaw heavy leptons in dilepton final states in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

Understand

A search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented.

• The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to 139 fb$^{-1}$ of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider.
• The analysis focuses on the final state with two light leptons (electrons or muons) of different flavour and charge combinations, with at least two jets and large missing transverse momentum.
• No significant excess over the Standard Model expectation is observed.