[séminaire] A dark matter search production in association with a Higgs boson decaying to bottom quarks with the ATLAS detector

by Dilia Portillo Quintero

Tuesday 23 Apr 2019, 11:00 → 12:00 Europe/Paris

Grand Amphi (LPSC)

A search for dark matter production in association with a Higgs boson decaying to b-quarks is presented using pp collisions at a centre-of-mass energy of √s=13TeV. The dataset has an integrated luminosity of 80fb−1 and was recorded with the ATLAS detector at the Large Hadron Collider. Selected collision events comprise large missing transverse momentum (MET) and either two b-tagged small radius jets or a single large radius jet containing two b-tagged subjets. This search uses a new variable: the object-based missing transverse momentum significance, which helps to separate events in which the reconstructed MET originates from weakly interacting particles as in the dark matter pair production, from those in which MET is consistent with contributions coming from particle measurement, resolutions and inefficiencies. With the help of this novel reconstruction technique, it is shown that background coming from pure strong interactions can be successfully rejected. The results are interpreted in the context of a simplified model (Z′-2HDM) which describes the interaction of dark matter and standard model particles via new heavy mediator particle.