Edinburgh Research Explorer

Dr Corrinne Mills

(Former employee or visitor)

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Research Interests

The possibility of discovering -- or excluding -- the Standard Model Higgs boson with the current LHC data led me into Higgs physics in mid-2011, but what intrigues me the most right now is the potential to observe, in its interactions, indirect evidence of further new particles, even those too massive to have been observed at colliders.  The Standard Model makes precise predictions for the relative decay rates of the Higgs boson to the other known fundamental particles, because the interactions with the one Higgs field provide all of their masses.  Any significant deviation from these predictions will point to the influence of physics beyond the Standard Model.  

Currently, I am collaborating with ATLAS colleagues to finalize our analysis of the data from the first LHC run, in the WW decay mode of the Higgs boson.  The WW decay mode in which each W boson decays to a charged lepton and a neutrino was critical for the discovery and remains important for the total rate measurement because of its large branching ratio and favourable signal-to-background ratio.  I have focused on background estimation techniques which use signal-depleted "control regions" in the data to reduce model dependence, a thread in my career going back to my Ph.D. work measuring the top pair cross section at the Tevatron.  In the last two years I have been co-editor of three public notes describing our results as the analysis progressed progressed from a search to a discovery to a measurement. Following that, I documented our WW analysis for the ATLAS Higgs boson couplings paper that established the new particle as the mechanism of electroweak symmetry breaking.  

With the analysis of the Run I data drawing to a close, the primary bosonic decay modes (W, Z, or photon pairs) of the new particle are now well-established, and evidence is accumulating in the most sensitive fermionic decay modes, to tau or bottom quark pairs.  A key prediction of the Standard Model is that the same Higgs boson is solely responsible for masses of all fermions and bosons, so more precise measurement of these modes is required to truly test the Standard Model, and this will be the core of my work in the next LHC run.  With additional data and an upgraded detector, there is great potential for improvement in the rate measurements for the fermionic decay modes, and I look forward to bringing my experience with background estimation and lepton identification to analysis of the b--anti-b quark decay mode of the Higgs boson.  To complement that work, I will study the identification of the hadronic particle "jets" produced by b quarks using precision tracking information.  

The scope of modern particle physics experiments is only possible because of the years of effort that go into their planning, particularly in detector research and development.  With that in mind, I have joined the Edinburgh team testing front-end readout chips for next-generation pixel tracking detectors.  In collaboration with others in the UK and elsewhere, we will develop this into a significant contribution to the upgraded ATLAS pixel detector, which we hope will start taking data in the high-luminosity LHC run scheduled to start early in the next decade.

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