Thomas J Phillips, Research Scientist  

Office Location: 267 Physics
Office Phone: (919) 660-2561
Email Address:
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Experimental high energy physics

PhD, Harvard University, 1986
MA, Harvard University, 1982
MS, Stanford University, 1980
BS, Stanford University, 1980

Research Categories: Experimental High Energy Physics

Current projects: CDF, ATLAS, Antimatter Gravity Experiment

Research Description:

Associate Research Professor Thomas J. Phillips' primary research is done at the Collider Detector at Fermilab (CDF), where protons and antiprotons were collided to produce high center-of-mass energies. This energy can produce massive particles such as the Higgs boson that are new to science.

Currently Professor Phillips is leading a working group that is improving the ability of CDF to identify jets coming from b quarks. If the Standard Model Higgs boson exists, current evidence indicates it should have a mass in the range where its primary decay will be into a pair of b quarks. The search for the Higgs is CDF's flagship analysis, and improving the algorithms used to identify b jets is leading to a significant improvement in the sensitivity for finding the Higgs boson. With this improved sensitivity, the CDF experiment should be sensitive to the Standard Model Higgs over the entire mass range where it is expected to be found. This means that CDF could rule out the existence of the Standard Model Higgs with 95% confidence if it does not exist and if there are no unfortunate statistical fluctuations in the background processes. If the Standard Model Higgs does exist, CDF can provide valuable evidence for this in the Higgs' primary decay channel.

In addition to contributing to the Higgs search, Professor Phillips analyzed the CDF data looking for signals of new (exotic) physics including extra dimensions and supersymmetry by looking for long-lived massive charged particles (CHAMPs). Most beyond-standard-model theories predict new massive particles, and most searches for these particles assume that they decay immediately. However, if they are stable long enough to traverse the detector, they would have evaded these searches. The CHAMPs analysis looked for charged particles with high momentum but low velocity, which is a signature for high mass. CHAMPs are predicted by many classes of theories, where the stability comes from weak coupling constants, limited phase space, or other constraints such as a new conserved (or nearly conserved) quantity.

In addition to the CHAMPs analysis, Professor Phillips participated in an analysis looking for new physics in events with W or Z bosons. The goal of this analysis was to look for deviations from Standard-Model predictions in the photons produced along with the W or Z boson. Deviations could be an indication of anomalous couplings to the W or Z boson.

Professor Phillips is founder of the Antimatter Gravity Experiment (AGE) and is spokesperson of the AGE collaboration. If funded, this experiment will make the first measurement of the gravitational force between the earth and antimatter. The plan is to use trapped antiprotons and positrons to make a slow beam of antihydrogen. The beam will be directed through an atomic interferometer, where the phase shift due to gravity will be measured.

Areas of Interest:
Higgs boson search
Charged Massive Stable Particles
W and Z bosons (including rare decays)
Antimatter Gravity
Electric Vehicle Power Sources

Recent Publications   (More Publications)

  1. Aaltonen, T. and others, Search for standard model Higgs boson production in association with a W boson at CDF, Physical Review D - Particles, Fields, Gravitation and Cosmology, vol. 85 no. 5 (2012), pp. 032008 [e032008], [doi]  [abs].
  2. Aaltonen, T. et al., Top-quark mass measurement using events with missing transverse energy and jets at CDF., Phys Rev Lett, vol. 107 no. 23 (December, 2011), pp. 232002, American Physical Society [22182082], [doi]  [abs].
  3. Aaltonen, T. et al., Observation of the baryonic flavor-changing neutral current decay Λb(0)→Λμ+μ-., Phys Rev Lett, vol. 107 no. 20 (November, 2011), pp. 201802, American Physical Society [22181723], [doi]  [abs].
  4. Aaltonen, T. et al., Search for New T' particles in final states with large jet multiplicities and missing transverse energy in p p collisions at sqrt[s] = 1.96 TeV., Phys Rev Lett, vol. 107 no. 19 (November, 2011), pp. 191803, American Physical Society [22181598], [doi]  [abs].
  5. Aaltonen, T. et al., Search for Bs0→μ+μ- and B0→μ+μ- decays with CDF II, Physical Review Letters, vol. 107 no. 19 (November, 2011), pp. 191801, American Physical Society [PhysRevLett.107.191801], [doi]  [abs].