Paul Tipton - Research

 

Our group is conducting research as part of the ATLAS experiment which collects data from proton-proton collisions at the LHC located at  CERN in Geneva Switzerland.  We have two main areas of research.

First, in collaboration with Prof. Sarah Demers’ group, we are taking the lead in a measurement of the quantum numbers of the newly discovered Higgs boson.  By studying the decay angular correlations of the Higgs decay to pairs of tau leptons, we will be sensitive to the charge conjugation and parity properties of the Higgs coupling to the tau.  This work will be an extension of a previous ATLAS publication, for which we hope to use our expertise in deep neural networks to gain sensitivity.

Secondly, in Yale’s Wright Lab we are helping to construct an upgrade to the ATLAS particle tracking system.   Planned upgrades to the LHC accelerator will open exciting new physics opportunities.  These upgrades will necessitate more collisions per beam crossing, which will require a new ATLAS tracker that is more radiation hard and has better spatial resolution.

In clean room facilities at Wright Lab, we are fabricating the support structures call stave cores.   Each stave core will have 28 thin silicon-wafer strip particle detectors mounted on it.  Staves will reside in the central (barrel) region of the new tracker.  Stave cores are fabricated with advanced composite materials such as carbon foam.  We are using robotic technology and thermal imaging for tests of parts and completed stave cores.

  

Previously our group conducted a number of research projects on ATLAS, including numerous results using the H->gamma gamma decay mode.  We conducted the first search for di-Higgs and made important contributions to subsequent searches, and we led the intitial effort to observe the Higgs being produced with top-quark pairs.  We worked with two other groups to set new limits on first and second-generation leptoquark production.  Next we performed a broad search for new exotic phenomenon that would give rise to events with three or more high energy leptons.   Our first analysi effort  on ATLAS helped establish that ATLAS was physics-ready.  We  made important contributions to the group effort that made the first measurement of the top cross section using the ATLAS detector.

Before joining ATLAS, our group had a successful program at Fermilab as part of the CDF Collaboration. Our group made essential contributions to the discovery of the  top quark and made subsequent measurements of its mass.  We searched for new objects that would decay into pairs of top quarks, and a searched for rare flavor-changing neutral current decays of the top.  We also performed a test for new physics in the kinematics of top decay products and a search for a charged Higgs in top decays.  The culmination of our program at CDF included the first evidence for photons produced with top quarks and the strongest evidence from the Tevatron for the Higgs boson that was subsequently discovered at the LHC.

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