Experimental High Energy Physics

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Research Talks Papers Courses

Research Activities

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 will be accessed by the LHC. So, after a decade of precision measurements at LEP, the next decade is expected to bring with it an era of new discoveries. Within the framework of the Standard Model, the elusive Higgs boson remains to be observed (or disproven). Beyond the Standard Model, there are numerous possibilities, some already imagined, others presumably not. Either way, the data from the LHC will provide us with our first glimpse of this new physics and is likely to mark the start of an entirely new era for both experimental and theoretical particle physics.

Several detectors of different types are under construction 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). First published results from this test have also recently appeared (the reference can be found below).

I also remain a member of the OPAL experiment and continue with analysis of the final data sample, searching for physics beyond the Standard Model, with a particular emphasis on supersymmetric models and recent theories which postulate the existence of large extra dimensions (low-scale gravity). Final publications based in part on this work appeared in 2006.

Recent Talks

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

The ATLAS Liquid Argon Calorimeter
NSS 2005, Puerto Rico, August 2005.
Contribution to conference record pdf file

SUSY Searches Using The ATLAS Detector at the LHC
DPF 2004, Riverside California, U.S.A, August 2004.
Contribution to conference proceedings ps S pdf

The ATLAS Detector at the Large Hadron Collider
Invited Talk, 59th CAP Congress, Winnipeg, June, 2004.

ATLAS Calorimetry at the Large Hadron Collider
Invited Talk, Western Regional Nuclear and Particle Physics Conference
Lake Louise, February 2004.

And Now, The End Is Near: Physics Results from LEP2
Invited Talk, Western Regional Nuclear and Particle Physics Conference
Lake Louise, February 2001

New Physics Searches Using Photonic Final States at LEP
IPP Tour, January 2001

OPAL Searches for Prompt Light Gravitino Production
DPF 2000, Columbus, Ohio, U.S.A, August 2000.
Contribution to conference proceedings

Searches for Extra Dimensions at LEP
SUSY 2000, 8th International Conference on Supersymmetries in Physics
CERN, Geneva, Switzerland, June 2000.

Physics at the TeV Scale: Discovery Prospects Using the ATLAS Detector at the LHC
Invited Talk, 55th CAP Congress, Toronto, June, 2000.

The Search for Supersymmetry
Colloquium, University of Alberta, 1998. Updated, Carleton University, 2000.

Selected Publications

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.

Searches for Gauge-Mediated SUSY Breaking Topologies in e+e- Collisions at LEP2
The OPAL Collaboration, (G. Abbiendi et al.), Eur.Phys.J. C46 (2006) 307-341.

Searches for Gauge-Mediated SUSY Breaking Topologies in e+e- Collisions at LEP2
The OPAL Collaboration, (G. Abbiendi et al.), CERN-PH-EP-2005-025 , accepted by Eur.Phys.J. .

Multi-Photon Events with Large Missing Energy in e+e- Collisions at roots = 192 - 209 GeV
The OPAL Collaboration, (G. Abbiendi et al.), CERN-PH-EP-2004-035, Phys. Lett. B602 (2004) 167-179.

Constraints on Anomalous Quartic Gauge Boson Couplings from vv gamma gamma and qq gamma gamma Events at LEP2
The OPAL Collaboration, (G. Abbiendi et al.), CERN-PH-EP-2004-003, Phys Rev D70 (2004) 032005.

Searches for Prompt Light Gravitino Signatures in e+e- Collisions at roots =189 GeV
The OPAL Collaboration (K. Ackerstaff et al.), CERN-EP-2000-078, Phys. Lett. B501 (2001) 12-27.

Photonic Events with Missing Energy in e+e- Collisions at roots = 189 GeV
The OPAL Collaboration (K. Ackerstaff et al.), CERN-EP-2000-050, Eur.Phys.J. C18 (2000) 253-272.

Search for Unstable Heavy and Excited Leptons at LEP2
The OPAL Collaboration (K. Ackerstaff et al.), CERN-EP/99-169, Eur. Phys. J. C14 (2000) 73-84.

Search for Anomalous Production of Photonic Events with Missing Energy in e+e- Collisions at roots = 130,136 and 183 GeV
The OPAL Collaboration (K. Ackerstaff et al.), CERN-EP/98-143, Eur. Phys. J. C8 (1999) 23-40.

Search for Anomalous Production of Photonic Events with Missing Energy in e+e- Collisions at roots = 130-172 GeV
The OPAL Collaboration (K. Ackerstaff et al.), CERN-PPE/97-132, Eur. Phys. J. C2 (1998) 607-625.

Search for Unstable Heavy and Excited Leptons in e+e- Collisions at roots = 170-172 GeV.
The OPAL Collaboration (K. Ackerstaff et al.), CERN-PPE/97-123, Eur. Phys. J. C1 (1998) 45-64.

Measurements of the B^0_s and Lambda_b Lifetimes
The OPAL Collaboration (K. Ackerstaff et al.), CERN-PPE/97-159, Phys. Lett. B426 (1998) 161-179.

Production of P-Wave Charm and Charm-Strange Mesons in Hadronic Z0 Decays
The OPAL Collaboration (K. Ackerstaff et al.), CERN-PPE/97-035, Z. Phys. C76 (1997) 425-440.

Teaching

PHYS 250S Electricity & Magnetism

PHYS 489/1489S Introduction to Particle Physics

PHYS 357S Introduction to Particle Physics (Spring 2006)

U of T Undergraduate Course Page