Dark Matter searches at the ATLAS experiment

The aim will be to use the Higgs boson as a 'portal' to probe the Dark Matter sector with the objective of either measuring or setting limits on Dark Matter production. There is great discovery potential in this sector because using the Higgs boson as a 'portal' into the Dark sector is independent of whether or not Dark Matter has a weak hypercharge. Should it turn out that Dark Matter has no such charge it could be that the Higgs would be the only way to probe the Dark sector.

The impact will be to set limits on Dark matter production at the LNC for a range of candidate masses. These searches do not depend on weak couplings of the DM because the Higgs boson couples to Dark Matter through its inertia. Inertia is the one property that we know Dark Matter has, therefore these sorts of Dark Matter searches are very general.

Should Dark Matter be discovered through these types of searches the impact will be exceptionally high. Certainly one or more Nobel prizes would be in the offing, but importantly for the field, entirely new questions would arise. Is this the ONLY Dark Matter form?

Are there excited states of Dark Matter and if so, can we produce them in our accelerators as well and measure their decays as they cascade down to the lightest Dark Matter particle. Are the properties of this Dark Matter that was found close to the properties of the Dark Matter that we see through its gravitational interactions thoughout the Universe?

Even without a discovery the impact of setting limits on the mass of the lightest Dark Matter particle narrows the search range for something that we know exists, but we have been unable thus far to find within our earth-based detectors outside its large scale gravitational influence.

Novel AI methods will be developed in this project in several sectors. First there will be continuing development in flavour tagging. The intention would likely be to use the decay of the Higgs bosons to b bbar pairs which it does 58% of the time (a very high Branching Ratio) and therefore it is important that the tagging of b jets have high efficiency over a wide range of jet energies and also a high rejection of background.

Additionally further, even more novel, Artificial Intelligence methods will be used to improve the resolution and scale of Missing energy measurements. Since Dark Matter is, at best, weakly charged (like a neutrino), production of Dark Matter leaves behing a momentum inbalance in the detector. Accurate measurement and scale of this missing energy is therefore critical to these searches.