Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at √s= 8 TeV with the ATLAS detector

A search is presented for production of dark-matter particles recoiling against a leptonically decaying Z
boson in 20.3 fb^−1 of pp collisions at √s= 8 TeV with the ATLAS detector at the Large Hadron Collider.
Events with large missing transverse momentum and two oppositely charged electrons or muons consistent
with the decay of a Z boson are analyzed. No excess above the Standard Model prediction is observed.
Limits are set on the mass scale of the contact interaction as a function of the dark-matter particle mass
using an effective field theory description of the interaction of dark matter with quarks or with Z bosons.
Limits are also set on the coupling and mediator mass of a model in which the interaction is mediated by a
scalar particle.