Luc Demortier

What I do:

I am a high energy physicist, member of the CDF ("Collider Detector at Fermilab") and CMS ("Compact Muon Solenoid") collaborations.

The CDF detector is located at the Fermi National Accelerator Laboratory near Chicago, IL. You can take a fascinating virtual tour of this experiment here... Its purpose is to study collisions between protons and antiprotons at the highest center-of-mass energy currently attainable in America (two trillion electron-volts!). I am particularly interested in the properties of the top quark, an elementary particle I helped discover in 1995. Other interests include the search for the Higgs boson and for phenomena not predicted by the standard model of elementary particles.

The CMS detector is located at CERN, the European particle physics center near Geneva, Switzerland. This experiment will start taking data in 2008 and will study proton-proton collisions at a center-of-mass energy seven times that of the Fermilab accelerator. Here too the objective will be to search for the Higgs boson and for effects that are not predicted by the standard model. Due to the theoretical incompleteness of the latter, such effects are expected, although noone knows yet which ones will actually show up.

At a more general level, I am interested in how we extract information from our observations, and I want to make sure that we do it right. I have been a member of the CDF Statistics Committee since its creation in the summer of 2000, and am now chairing the CMS Statistics Committee. The purpose of these committees is to study statistical issues that are relevant for data analysis in high energy physics, provide advice to their respective collaborations, and develop methods for coordinating and combining results between experiments.

Pictures from some recent conferences and workshops I attended:

September 2005 PhyStat conference in Oxford, U.K.

March 2006 workshop at SAMSI, N.C.

July 2006 workshop in Banff, Canada.

Selected talks and publications:

• Technical reports
• Conference proceedings
• Miscellaneous talks
• Refereed publications

Back to top.

• Technical reports (only documents that are not restricted by CDF or CMS can be downloaded),
  • on statistics:
    1. Simple facts about p-values, CDF note 8023, January 2006 (with Craig Blocker et al.)
    2. Objective Bayesian upper limits for Poisson processes, CDF note 5928, June 2005.
    3. A convolution method for folding systematic uncertainties into likelihood functions, CDF note 5305, June 2005.
    4. Recommendations concerning limits, CDF note 7739, May 2005 (with Craig Blocker et al.)
    5. Interval estimation in the presence of nuisance parameters. 1. Bayesian approach. arXiv:physics/0409129 v1, 27 September 2004 (with Joel Heinrich et al.)
    6. Everything you always wanted to know about pulls, CDF note 5776, August 2002 (with Louis Lyons).
    7. Combining the top quark mass results for Run 1 from CDF and D0, Fermilab report no. FERMILAB-TM-2084, September 1999 (with the Top Averaging Group).
    8. Equivalence of the best-fit and covariance-matrix methods for comparing binned data with a model in the presence of correlated systematic uncertainties, CDF note 8661, April 1999.
    9. Assessing the significance of a deviation in the tail of a distribution, CDF note 3419, November 1995.
  • on physics:
    1. Measurement of the top quark mass using the template method in the lepton plus jets channel with in situ W->jj calibration at CDF-II, CDF note 7680, October 2005 (with the CDF collaboration).
    2. Updated top quark mass measurement in the lepton+jets channel using the jet probability algorithm, CDF note 7637, May 2005 (with the CDF collaboration).
    3. Search for W-pair production using jet charge, charged track multiplicity and charm jet tagging, CDF note 5935, February 2003 (with Hideaki Takano et al.).
    4. Search for single-top production with CDF, CDF note 5477, November 2000 (with Toshiaki Kikuchi et al.).
    5. Combining the top quark mass results for Run 1 from CDF and D0, Fermilab report no. FERMILAB-TM-2084, September 1999 (with the Top Averaging Group).

  Back to top, or to selected talks and publications.

• Conference proceedings:
  1. P values and nuisance parameters, in the proceedings of the PhyStat 2007 conference, CERN, Geneva, Switzerland, June 2007.
  2. Joel Heinrich's Review of the Banff challenge on upper limits, also in the PhyStat 2007 proceedings, includes a comparative discussion of my contribution to the Banff challenge.
  3. Bayesian reference analysis, in the proceedings of the PhyStat 2005 conference, Oxford, UK, September 2005.
  4. Generalized frequentist methods for calculating p-values and confidence intervals, in the proceedings of the PhyStat 2005 conference, Oxford, UK, September 2005.
  5. Constructing ensembles of pseudo-experiments, in the proceedings of the PhyStat 2003 conference, SLAC, Stanford, CA, September 2003.
  6. Bayesian treatments of systematic uncertainties, in the proceedings of the PhyStat 2002 conference, Durham, UK, March 2002.

  Back to top, or to selected talks and publications.

• Miscellaneous talks:
  1. Bayesian statistics from subjective quantum probabilities to objective data analysis, Caltech informal high energy physics seminar, 29 April 2008.
  2. P-values and nuisance parameters, slides from the plenary talk given at PhyStat 2007.
  3. Bayesian reference analysis, talk given at PhyStat 2005.
  4. Bayesian reference analysis, an abbreviated version of the PhyStat2005 talk prepared for the Rockefeller HEP group.
  5. Generalized frequentist methods for computing p-values and confidence intervals, talk given at PhyStat 2005.
  6. Bayesian upper limits for Poisson processes, talk given as part of a CDF statistics committee presentation at the CDF Joint Physics meeting in February 2005.
  7. Ordering rules as criteria of inductive inference, a short presentation to the CDF statistics committee in April 2004.
  8. Conditioning, a short presentation to the CDF statistics committee at our Oxford meeting in 2003.

  Back to top, or to selected talks and publications.

• Refereed publications, via Spires

  Back to top, or to selected talks and publications.