A search for an unexpected asymmetry in the production of e + μ − and e − μ + pairs in proton–proton collisions recorded by the ATLAS detector at s = 13 TeV

This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e + μ − and e − μ + pairs to constrain physics processes beyond the Standard Model. It uses 139 fb − 1 of proton–proton collision data recorded at s = 13 TeV at the LHC. Targeting sources of