An investigation of the sensitivity of LHC dark matter searches at √ s = 13 TeV to dark Higgs models

Abstract

There is five times as much dark matter (DM) than regular matter in the universe. However, all current evidence of DM is purely gravitational and the nature of DM remains an unknown question in both collider searches and astrophysical searches. Many potential DM candidates have been proposed, among which the weakly interacting massive particles (WIMPs) are most well-motivated. This analysis details a search for the production of such particles at the Large Hadron Collider (LHC) with a new model. In this model, a Dark Higgs boson is introduced in order to generate the masses of the particles in the dark sector and it allows the constraints from the dark matter relic abundance to be relaxed by opening up a new annihilation channel. The decay ratio of a dark Higgs →bb is set to be 100% in this analysis and the decay of the dark Higgs is reconstructed as either a single large-radius jet with substructures or a pair of small-radius jets. Large missing transverse momentum is also considered in reconstruction. The expected experimental signatures are characteristic large-radius boosted jets in association with missing transverse momentum. The
αT variable and other several kinematic variables are employed later for further comparison. Finally, the expected exclusion region for analyses sensitive to these signatures at 95% confidence level (CL) with an integrated luminosity of 3.2fb−1 are plotted and conclusions are drawn.

Date of Award	23 Jan 2019
Original language	English
Awarding Institution	The University of Bristol
Supervisor	Bjoern Penning (Supervisor) & Henning U Flaecher (Supervisor)