Wendy Taylor Ph.D. (Toronto)  Professor of Physics This e-mail address is being protected from spambots. You need JavaScript enabled to view it Research Fields: High Energy Physics Research specialization: Experimental particle physics (see http://www.hep.yorku.ca). Publications

Particle physics is the study of the smallest constituents of matter and the four fundamental forces between them. Our current understanding is that the world is made up of six quarks and six leptons, each apparently grouped into pairs, forming three similar families of matter. Research shows that quarks and leptons do not have any substructure, that is, that they are the fundamental particles. Each of these particles is partnered with an antiparticle with the same mass but the opposite charge. The standard theoretical model of particle physics does not explain why these particles appear in three families, nor does it predict the particle masses. At a cosmological level, we do not understand why the universe appears to be dominated by matter as opposed to antimatter, nor do we understand the source of the “dark matter” that represents 23% of the matter in the universe.Perhaps there are particles we have yet to discover. To help answer these questions, we need to go back to the Big Bang, when the universe was minute and the temperatures and densities of matter were enormous. Particle accelerators are the tools we use to recreate the conditions of the universe shortly after the Big Bang.

I am a member of the ATLAS experiment at the Large Hadron Collider at CERN, in Geneva, Switzerland. The Large Hadron Collider is the world's highest energy accelerator, smashing protons at a collision energy of 8 TeV. The ATLAS experiment, an international collaboration of 3000 physicists from more than 170 universities and laboratories in 38 countries, has a large Canadian effort. On July 4, 2012, ATLAS, and its competitor experiment CMS, announced the discovery of a new particle. This particle has a mass of 126 GeV (equivalent to the mass of 126 protons) and appears to have the properties of the Higgs boson, a particle postulated to be the reason why some particles have mass while others, like the photon, are massless. ATLAS expects to double the size of its data set by the end of 2012 and this will allow us to study the properties of this new particle to see if it is indeed the Higgs boson or perhaps it is just the first of a new class of particles.

ATLAS is also search for evidence of Supersymmetry, a theory that predicts a series of particles that are related to the known fundamental particles.  Supersymmetry is an attempt to unify the strong and weak forces in the Standard Model.  One of the particles predicted by Supersymmetry could be the source of the dark matter. Whether or not Supersymmetry exists, ATLAS is certain to discover new physics. The York ATLAS group is collaborating with York theorist Veronica Sanz on a search for LeptoSUSY, a Supersymmetry model that yields many leptons.  We have completed a search for Z’ bosons decaying into an electron-muon pair via intermediate tau pairs (a tau is an unstable lepton). Z bosons are particles that mediate the electroweak force so the existence of a Z’ boson, a heavy version of the Z boson, would definitely indicate new physics.  Finally, on June 14, 2012 we released the results of a search for magnetic monopoles at ATLAS. All magnetic objects that have ever been observed have a north pole at one end and a south pole at the other end. A magnetic monopole is a particle postulated to carry only a south or a north pole. If a magnetic monopole exists, theory shows that this would explain why there appears to be a fundament unit of electric charge.  This is one of the outstanding mysteries in particle physics today!  Unfortunately, we saw no sign of magnetic monopoles so far.

The York ATLAS group is also working on readout electronics (including firmware development) for the Transition Radiation Tracker in the ATLAS inner detector. My electronics test and development laboratory, funded by a generous grant from the Canadian Foundation for Innovation, includes the state of the art equipment necessary for such leading edge electronics projects. We are currently preparing a proposal to build new custom electronics to select magnetic monopoles in real time at ATLAS. If this proposal is approved, this new trigger will be built and installed in 2014 and will dramatically improve our ability to observe magnetic monopoles in ATLAS. We have studied the expected performance of both the track reconstruction and the electron identification of the Transition Radiation Tracker for high luminosity LHC conditions. In the past, we have worked on jet reconstruction algorithms for the High Level Trigger and the offline selection.