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Peter Krieger


Experimental High Energy Physics

Telephone: (416) 978-2950
Fax: (416) 978-8221

Research Talks Papers Courses

BSc., Dalhousie (1985)
MSc, University of Toronto (1988)
PhD, University of Toronto (1994)
Research Associate, Carleton University (OPAL) (1994-1998),
Research Associate, Carleton University (ATLAS/OPAL) (1998-2001),
IPP Research Scientist/Assistant Professor, University of Toronto (2001-2004),
Associate Professor, University of Toronto (2005 - 2014)
Professor, University of Toronto (2014)

Research Activities

My research focus is ultimately on the search for physics beyond the so-called Standard Model of Particle Physics. The next few years will be an especially exciting time for our field. In Sept. 2008 CERN's Large Hadron Collider (LHC), the highest-energy collider ever constructed, circulated proton beams for the first time, an event that was well publicized in the national and international press. An equally well publicised incident required the shutdown of the LHC soon thereafter, for repairs that were completed in mid-2009. The LHC is scheduled to begin producing proton-proton collisions in late 2009 and to run for about one year before shutting down for further maintenance. Because the fundamental interactions occuring in such collisions are between constituents of the protons, such collisions sweep out a range of centre-of-mass energies up to a maximum of 14 TeV. This is a feature of hadron colliders that makes them particularly well suited to the discovery of new phenomena.

The current theory describing our understanding of the fundamental constituents of matter and their interactions, the Standard Model, has been extraordinarily successful and has survived all the experimental tests to which it has so far been subjected, some of them tremendously precise. The Large Electron-Positron (LEP) collider at CERN was decomissioned in 2001 after over a decade of data taking, at centre-of-mass energies between 90 and 209 GeV, which resulted in confirmation of the Standard Model to very high precision, especially in the electroweak sector which it was designed to study (see LEP Electroweak Working Group web pages ).

However, despite the successes of the Standard Model, there are strong theoretical motivations for the widespread belief that this theory represents a low-energy effective theory that cannot survive intact to arbitrarily high energy. Furthermore, some theoretical arguments point to a scale for physics beyond the SM that is around 1 TeV, an energy range that is accessible at the LHC. At the start of the LHC experimental program, the Higgs boson, predicted by the Standard Model, had yet to be observed. It was discovered by the ATLAS and CMS collaborations in 2012. Searches for physics Beyond the Standard Model, however, have so far not found significant evidence for new phenomena. These searches continue.

Several detectors of different types were constructed for use at the LHC. Two of these, CMS and ATLAS, are general purpose detectors designed to have broad capabilities for the discovery of the Higgs boson as well as for new physics searches. The Canadian high-energy physics commumity plays an important role in the ATLAS Collaboration , with responsibilites for construction of significant portions of the liquid-argon calorimeters in the endcap region of the detector. For years, much of my effort was focussed on the completion and testing of the ATLAS forward calorimeter, modules of which were constructed at University of Arizona, Carleton University in Ottawa, and here at U of T. In the summer of 2003 the first full FCal was tested in electron and hadron beams at CERN. First published results from these tests can be found in the publications section, below. In the summer of 2004 the FCal group also took part in tests of a slice of a full endcap calorimeter. This combined endcap testbeam is designed to study the transition region between the forward calorimeters and the other endcap calorimeters, the electromagnetic endcap calorimeter (EMEC) and the hadronic endcap calorimeter (HEC). Published results from this test can be found below.

Recent Talks

Standard Model and Higgs Physics at the HL-LHC with ATLAS and CMS
LHCP 2016, Lund, Sweden, June, 2016.

Upgrade Plans for ATLAS Forward Calorimetry for the HL-LHC
CHEF 2013, Paris, France, April, 2013.
Contribution to conference record pdf file

Inclusive Jet and Multi-jet Production at ATLAS and CMS
PLHC 2012, Vancouver, BC, June, 2012.

The ATLAS Liquid Argon Calorimeter: One Year of LHC Operation and Future Upgrade Plans for HL-LHC
ANIMMA 2011, Ghent, Belgium, June , 2011.
Contribution to conference record pdf file

First ATLAS Results from Lead-Lead Collisions at the Large Hadron Collider
CAP Congress 2011, St. John's, NL, June, 2011.

The First LHC Beams in ATLAS
Aspen Winter Conference, Aspen, Colorado, February, 2009.

The ATLAS Experiment at the CERN Large Hadron Collider
Invited Talk, WNPPC'08, Banff, February, 2008.

Performance of the ATLAS Liquid Argon Forward Calorimeter in Beam Tests
Como, Italy, October 2007.
Contribution to conference record pdf file

Selected Publications

Observation of a new particle in the search for the Standard Model Higgs Boson with the ATLAS detector at the LHC.
ATLAS Collaboration (G. Aad et al.),
Phys. Lett. B 716 (2012) 1.

The ATLAS Forward Calorimeters
A. Artamonov et al., JINST 3 (2008) P02010

Performance of the ATLAS Liquid Argon Endcap Calorimeter in the Pseudorapidity Region 2.5 < |eta| <4.0 in Beam Tests.
J. Pinfold et al., NIM A 593, (2008) 324-342.

Energy Calibration of the ATLAS Liquid Argon Forward Calorimeter
J.P. Archambault et al., JINST 3 (2008) P02002

Electron Signals in the Forward Calorimeter Prototype for ATLAS
J.C. Armitage et al., JINST 2 (2007) P11001.


In recent years I have taught mainly in our Undergraduate Advanced Lab

This site is maintained by Peter Krieger.