Research Program
I am an experimental high energy physicist and member of the CMS collaboration at the Large Hadron Collider (LHC) at CERN. A good starting point for non-experts is the LHC Wikipedia page.
My group has for many years searched for supersymmetry (SUSY) with jets + missing energy, dilepton final states, and searched for light top squarks motivated by naturalness ideas. We also contributed directly to the discovery of the Higgs boson via the WW channel, and made precision measurements of SM processes including top pair and W pair production. I co-led the CMS top and SUSY analysis groups for two year periods, starting in 2008 and 2015, respectively.
More recently we have worked toward the first observation of SM four-top production, studied Higgs production in conjunction with top-antitop pairs, measured the Higgs width, studied tri-boson production, searched for long-lived particles decaying into muon pairs, and probed flavor-changing neutral currents of top quarks and Higgs bosons. Going forward, the program centers on Higgs boson studies and exotic new physics searches.
On the instrumentation side, we completed an upgrade of CMS muon system electronics and are engaged in a further upgrade for the upcoming High Luminosity LHC era. We continue to contribute to the maintenace and operation of the muon detectors. In earlier times we had worked on muon identification and reconstruction, missing transverse energy studies, photon coversion identification, physics dataset definition, and the development of event visualization tools. Furthermore, a large fraction of the modules for the CMS tracker were assembled in our lab on the UCSB campus between 2003 and 2006. We participate in the Milliqan experiment searching for millicharged particles, and on a multidisciplinary program to apply machine learning techniques to clinical medical problems.
Teaching
I have taught physics at all levels at UCSB, from lower-division physics for life science majors to particle physics and statistical methods for advanced graduate students.
Spring 2026
I am teaching a graduate class on statistics for particle physics and a class on
modern physics for sophomore physics majors.
Selected Publications
Full list available via iNSPIRE (HEP) and PubMed (ML/Medicine).
2026–
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2026
Anomaly Detection for Automated Data Quality Monitoring in the CMS DetectorEPJ Res. Infrastruct. 10, 4 (2026) DOI
2021–2025
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2025
Search for the nonresonant and resonant production of a Higgs boson in association with an additional scalar boson in the γγττ final state at √s = 13 TeVSubmitted to JHEP arXiv:2506.23012
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2025
Search for a new scalar resonance decaying to a Higgs boson and another new scalar particle in the final state with two bottom quarks and two photons at √s = 13 TeVJHEP 2025, 178 (2025) DOI
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2025
Search for millicharged particles in proton-proton collisions at √s = 13.6 TeVPhys. Rev. Lett. 135, 121802 (2025) DOI
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2025
Measurement of WWZ and ZH production cross sections at √s = 13 and 13.6 TeVPhys. Rev. Lett. 135, 091802 (2025) DOI
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2024
A Machine Learning Derived Risk Score Improves Prediction of Outcomes Post-LVAD Implantation: An Analysis of the INTERMACS databaseJournal of Cardiac Failure 31(4), 679–688 (2024) DOI
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2024
Performance of Risk Models to Predict Mortality Risk for Patients with Heart Failure: Evaluation in an Integrated Health SystemClinical Research in Cardiology 113, 1343–1354 (2024) DOI
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2023
A machine learning-derived risk score predicts mortality in East Asian patients with acute heart failureEuropean Journal of Heart Failure (2023) DOI
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2023
Mortality Prediction in Patients With or Without Heart Failure Using a Machine Learning ModelJACC: Advances 2(7), 100554 (2023) DOI
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2023
Search for a high-mass dimuon resonance produced in association with b-quark jets at √s = 13 TeVJHEP 10 (2023) 43 Inspire
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2022
Improving clinical trial efficiency using a machine learning-based risk score to enrich study populationsEur J Heart Fail. (2022) DOI
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2022
Perspective: An upset to the standard modelScience 376, 136 (2022) DOI
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2022
First evidence for off-shell production of the Higgs boson and measurement of its widthNat. Phys. (2022) DOI
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2022
Search for flavor-changing neutral current interactions of the top quark and Higgs boson in final states with two photons at √s = 13 TeVPhys. Rev. Lett. 129, 032001 (2022) DOI
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2022
Search for long-lived particles decaying into muon pairs in proton-proton collisions at √s = 13 TeVJHEP 04 (2022) Inspire
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2021
Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at √s = 13 TeVEur. Phys. J. C81 (2021) 970 DOI
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2021
Machine Learning Applications in Heart Failure Disease Management: Hype or Hope?Current Treatment Options in Cardiovascular Medicine 23(6), 35 (2021) DOI
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2021
Sensitivity to millicharged particles in future proton-proton collisions at the LHCPhys. Rev. D104 (2021) 032002 DOI
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2021
Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at √s = 13 TeVJHEP 07 (2021) 027 DOI
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2021
A Machine Learning risk score predicts mortality across the spectrum of Left Ventricular Ejection FractionEur J Heart Fail. (2021) DOI
2016–2020
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2020
Search for millicharged particles in proton-proton collisions at √s = 13 TeVPhys. Rev. D102 (2020) 3, 032002 Inspire
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2020
Measurements of tt̄H production and the CP structure of the Yukawa interaction between the Higgs boson and top quark in the diphoton decay channelPhys. Rev. Lett. 125 (2020) 6, 061801 Inspire
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2020
Reinterpretation of LHC Results for New Physics: Status and Recommendations after Run 2SciPost Phys. 9, 022 (2020) DOI
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2020
Search for physics beyond the standard model in events with jets and two same-sign or at least three charged leptons at √s = 13 TeVEur. Phys. J. C80 (2020) 8, 752 Inspire
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2020
Search for direct top squark pair production in events with one lepton, jets, and missing transverse momentum at 13 TeVJHEP 05 (2020) 032 Inspire
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2020
Searches for physics beyond the standard model with the MT2 variable in hadronic final states with and without disappearing tracks at √s = 13 TeVEur. Phys. J. C80 (2020) 3 Inspire
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2020
Search for production of four top quarks in final states with same-sign or multiple leptons at √s = 13 TeVEur. Phys. J. C80 (2020) no.2, 75 Inspire
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2019
Improving risk prediction in heart failure using machine learningEur J Heart Fail. (2019) DOI
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2019
Search for the production of W±W±W∓ events at √s = 13 TeVPhys. Rev. D100 (2019) 012004 Inspire
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2018
Constraints on models of scalar and vector leptoquarks decaying to a quark and a neutrino at √s = 13 TeVPhys. Rev. D98 (2018) 032005 Inspire
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2018
Search for standard model production of four top quarks with same-sign and multilepton final states at √s = 13 TeVEur. Phys. J. C78 (2018) 140 Inspire
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2017
Search for top squark production in pp collisions at √s = 13 TeV using single lepton eventsJHEP 10 (2017) 019 Inspire
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2017
Search for electroweak production of charginos and neutralinos in WH events at √s = 13 TeVJHEP 11 (2017) 029 Inspire
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2017
Search for new phenomena with the MT2 variable in the all-hadronic final state at √s = 13 TeVEur. Phys. J. C77 (2017) 710 Inspire
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2017
Search for physics beyond the standard model in events with two same-sign leptons, missing transverse momentum, and jets at √s = 13 TeVEur. Phys. J. C77 (2017) 578 Inspire
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2017
Searches for pair production of third generation squarks at √s = 13 TeVEur. Phys. J. C77 (2017) 327 Inspire
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2016
Search for new physics in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum at √s = 13 TeVJHEP 13 (2016) 1612 Inspire
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2016
Search for new physics in same-sign dilepton events at √s = 13 TeVEur. Phys. J. C76 (2016) 439 Inspire
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2016
A Letter of Intent to install a milli-charged particle detector at LHC P5 (A. Ball et al.)
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2016
Search for new physics with the MT2 variable in all-jets final states at √s = 13 TeVJHEP 10 (2016) 006 Inspire
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2016
Measurements of tt̄ charge asymmetry using dilepton final states in pp collisions at √s = 8 TeVPhys. Lett. B760 (2016) 365 Inspire
2011–2015
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2014
Measurement of top quark-antiquark pair production in association with a W or Z boson at √s = 8 TeVEur. Phys. J. C74 (2014) 3060 Inspire
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2014
Measurements of the tt̄ charge asymmetry using the dilepton decay channel at √s = 7 TeVJHEP 04 (2014) 191 Inspire
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2014
Measurement of Higgs boson production and properties in the WW decay channel with leptonic final statesJHEP 01 (2014) 055 Inspire
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2014
Search for new physics in events with same-sign dileptons and jets at √s = 8 TeVJHEP 01 (2014) 163 Inspire
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2014
Measurements of tt̄ spin correlations and top-quark polarization using dilepton final states at 7 TeVPhys. Rev. Lett. 112, 182001 (2014) Inspire
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2013
Search for top-squark pair production in the single-lepton final state at √s = 8 TeVEur. Phys. J. C73 (2013) 2677 Inspire
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2013
Search for new physics in events with same-sign dileptons and b jets at √s = 8 TeVJHEP 03 (2013) 037 Inspire
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2012
Search for electroweak production of charginos and neutralinos using leptonic final states at √s = 7 TeVJHEP 1211 (2012) 147 Inspire
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2012
Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHCPhys. Lett. B716, 30 (2012) Inspire
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2012
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energyPhys. Rev. Lett. 109, 071803 (2012) Inspire
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2012
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy at √s = 7 TeVPhys. Lett. B718, 815 (2013) Inspire
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2012
Search for new physics in events with same-sign dileptons and b-tagged jets at √s = 7 TeVJHEP 08 (2012) 110 Inspire
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2012
Search for physics beyond the standard model in events with a Z boson, jets, and missing transverse energy at √s = 7 TeVPhys. Lett. B716, 260 (2012) Inspire
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2012
Search for heavy, top-like quark pair production in the dilepton final state at √s = 7 TeVPhys. Lett. B716, 103 (2012) Inspire
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2012
Search for the standard model Higgs boson in the H→ZZ→2ℓ2ν channel at √s = 7 TeVJHEP 1203 (2012) 040 Inspire
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2012
Search for the standard model Higgs boson decaying to a W pair in the fully leptonic final state at √s = 7 TeVPhys. Lett. B710, 91 (2012) Inspire
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2011
Search for Same-Sign Top-Quark Pair Production and Limits on Flavour Changing Neutral Currents in the Top Sector at √s = 7 TeVJHEP 1108 (2011) 005 Inspire
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2011
Measurement of the tt̄ production cross section and the top quark mass in the dilepton channel at √s = 7 TeVJHEP 1107 (2011) 049 Inspire
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2011
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy at the LHCJHEP 06 (2011) 077 Inspire
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2011
Search for Physics Beyond the Standard Model in Opposite-Sign Dilepton Events at √s = 7 TeVJHEP 1106 (2011) 026 Inspire
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2011
Measurement of WW Production and Search for the Higgs Boson in pp Collisions at √s = 7 TeVPhys. Lett. B699, 25 (2011) Inspire
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2011
First Measurement of the Cross Section for Top-Quark Pair Production in Proton-Proton Collisions at √s = 7 TeVPhys. Lett. B695, 424 (2011) Inspire
2006–2010
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2010
Missing ET in 0.9 and 2.36 TeV pp Collisions
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2010
Performance of Track-Corrected Missing Transverse Energy in CMS
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2010
Performance of CMS Muon Reconstruction in Cosmic-Ray EventsJINST 5 T03022 (2010) Inspire
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2006
Search for rare quark-annihilation decays, B−→Ds(*)−ϕPhys. Rev. D73, 011103 (2006) Inspire
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2006
Study of the decay B̄0→D*+ωπ−Phys. Rev. D74, 012001 (2006) Inspire
2001–2005
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2005
Measurement of the Charge Collection Efficiency after Heavy Non-Uniform Irradiation in BaBar Silicon DetectorsIEEE Trans. Nucl. Sci. 52, 1054 (2005) arXiv
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2005
Search for b→u transitions in B−→D0K− and B−→D*0K−Phys. Rev. D72, 032004 (2005) Inspire
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2004
Search for B± → [K∓π±]DK± and upper limit on the b→u amplitude in B±→DK±Phys. Rev. Lett. 93, 131804 (2004) Inspire
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2004
Silicon Tracker Module Assembly at UCSB
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2004
Measurement of the branching fraction and polarization for the decay B−→D*0K*−Phys. Rev. Lett. 92, 141801 (2004) Inspire
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2002
Measurement of the CP asymmetry amplitude sin2β with B0 mesonsPhys. Rev. Lett. 89, 201802 (2002) Inspire
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2002
Measurement of branching fractions for exclusive B decays to charmonium final statesPhys. Rev. D65, 032001 (2002) Inspire
1996–2000
1991–1995
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1995
Observation of top quark production in pp̄ collisions with the CDF detector at FermilabPhys. Rev. Lett. 74, 2626 (1995) Inspire
- 1994
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1993
A measurement of the bottom quark production cross section in 1.8 TeV p-p̄ collisions using muons from b-quark decaysPhys. Rev. Lett. 71, 2396 (1993) Inspire
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1992
Limit on the top quark mass from proton-antiproton collisions at √s = 1.8 TeVPhys. Rev. D45, 3921 (1992) Inspire
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1991
Search for W′→eν and W′→μν in p-p̄ collisions at √s = 1.8 TeVPhys. Rev. Lett. 67, 2609 (1991) Inspire
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1991
Measurement of σ(W→eν) and σ(Z→ee) in p-p̄ collisions at √s = 1800 GeVPhys. Rev. D44, 29 (1991) Inspire
1986–1990
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1990
Measurement of the ratio σ(W→eν)/σ(Z→ee) in p-p̄ collisions at √s = 1.8 TeVPhys. Rev. Lett. 64, 152 (1990) Inspire
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1988
A search for the decay K+→π+μ+e−Phys. Rev. Lett. 61, 2062 (1988) Inspire
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1987
Search for short-lived neutral particle emitted in K+ decayPhys. Rev. Lett. 59, 2832 (1987) Inspire
Selected Talks & Lectures
Most Recent (2020–present)
- Shiv Nadar University (India) Colloquium, 2025
- Discoveries at Hadron Colliders, Symposium in honor of Thomas Müller 70th Birthday, Karlsruhe, 2023
- Responsible Machine Learning Summit, UCSB, 2022
- Two Lectures at the Hunting SUSY at the HL-LHC School, ICTS Bangalore, India, 2021
- Hong Kong University Colloquium, 2021
Older
- APS April Meeting, Denver, 2019
- Two Lectures at the CERN-FNAL Summer School, Fermilab, 2018
- Reinterpretations Workshop, Plenary, CERN, 2016
- Mitchell Workshop, Plenary, College Station (TX), 2016
- Wine and Cheese Seminar, Fermilab, 2016
- University of Illinois Colloquium, 2016
- Seminar, Texas A&M, 2014
- AAAS Annual Meeting, Boston, 2013
- SUSY12 Plenary, Beijing, 2012
- Seminar, Fermilab, 2012
- UCSB Colloquia, 2012
- Seminar, Galileo Galilei Institute, 2011
- KITP Seminar, 2010
- Aspen Conference, 2010
- Seminar, University of Rome La Sapienza, 2010
- KCRW Radio Interview, 2009
- UCSB Colloquium, 2009
- LIP (Lisbon) Seminar on the Top Quark, 2008
- Anacapa High School, 2008
- TASI Summer School, 2007: Lecture 1, Lecture 2, Lecture 3
- LHC Olympics, 2006