Experimental Particle Physics Research Group

Precision Measurements of the Higgs, Top, and More

The discovery of the Higgs boson by the ATLAS and CMS collaborations in 2012 was one of the most important advances in high energy physics, bringing an end to decades of searching. Since then focus has shifted to understanding more about this new particle in order to give us a glimpse of potential physics beyond the Standard model. Members of the Sussex EPP group are studying least understood aspect of the properties of the Higgs boson: the way that it interacts with the top quark.

Lily and Emma championed the inclusion of the first `boosted ttH' analysis measurement in the recent observation of a Higgs boson in association with top quarks. Boosted objects can often be uncovered by utilising new techniques known as jet grooming and substructure, combined with machine learning algorithms.
Lily, Emma and Dan are using a jet substructure technique called Soft Drop to reduce the flavour-tagging uncertainties associated with the ttbb measurement. The smaller the uncertainties associated with a measurement, the more we are able to see of how the universe is put together.
Parton Distribution Functions.
Iacopo, Tom, Kerim, Meirin and Kate are measuring the rate and kinematic properties of the production of a top pair in association with a Z boson. The process has been measured for the first time at the LHC. It is rare, therefore new physics might be less hidden by known physics here than elsewhere.