PROFESSOR DAVID W. HERTZOG
Department of Physics University of Washington
Box 351560, Seattle WA 98195
(206) 543-0839 begin_of_the_skype_highlighting(206) 543-0839end_of_the_skype_highlighting begin_of_the_skype_highlighting
College of William and Mary Ph.D., Physics 1983
Carnegie-Mellon University Research Associate 1983-86
University of Illinois Assistant Professor, Physics 1986-92
University of Illinois Associate Professor, Physics 1992-97
University of Illinois Professor, Physics 1997-2010
University of Washington Professor, Physics 2010-
Current research: I am involved in a series of high-precision experiments involving muons:
I am co-spokesman of MuLan and the New g-2 Experiment. Additionally, I supervise a Ph.D. student who is carrying out an analysis of Belle data to help determine the hadronic vacuum polarization component of the standard model theory for the muon g-2. My group is also known for our work in developing various detectors, especially electromagnetic calorimeters using scintillating fibers.
Honors and awards:
teaching and training (at Illinois) Developed new Modern
Physics Laboratory course featuring research-style data
recording, analysis techniques, report writing, and oral
presentations. Developed two-semester Introduction
to Physics Research/Senior Thesis course sequence to
prepare advanced undergraduates for physics careers.
Served on the design teams
for new introductory physics courses, which incorporate
active-learning pedagogy. Designed and implemented all new
laboratories for two semesters of algebra-based introductory
physics courses. Wrote The
Problem Solver for Physics 102 Discussion sections.
Room for Practical Physics: How Things Work course.
Co-teacher for several years in the
Science literacy and public outreach: Founded and ran for two years the Saturday Physics Honors Program aimed at high school students, but also attended by the general public. Several invited talks to under-graduates and high-school physics teachers and public forums on muon g-2 experiments and more recently on The World's Greatest Scientific Instruments.
Ph.D. Students Supervised (academic research institution if applicable):
R. Tayloe (Indiana), S.A. Hughes, P.E. Reimer (ANL), J. Ritter, T. Jones, B. Bunker, F.E. Gray (Regis Univ.), C. Polly (Fermilab), D.B Chitwood, S. Clayton*,** (LANL), D. Webber (Wisconsin). Current students: J. Crnkovic, B. Kiburg*, S. Knaack*, M. Murray*
*co-supervised by P. Kammel;
**co-recipient APS Dissertation Prize in Nuclear Physics, 2009.
Postdoctoral Fellows Supervised:
P.G. Harris, S.A. Sekykh, G. Onderwater, F. Mulhauser, C. Ozben, R. McNabb, P. Winter, S. Kizilgul
Some special papers of interest:
Final report of the E821 muon anomalous magnetic moment measurement at BNL; Muon g-2 Collaboration, G.W. Bennett et al., Phys. Rev. D 73, 072003 (2006) (pdf) This is the summary paper of the BNL experiment with final numbers from all runs.
The Brookhaven Muon Anomalous Magnetic Moment Experiment, David W. Hertzog and William M. Morse, Annu. Rev. Nucl. Part. Sci. 2004. 54:141-74. (pdf) This is an experimental overview for general readership.
Muons: Particles of the Moment (Physics World, March 04) My discussion of the muon g-2 experiment for non-experts in pdf at abot the time of the fun controversial issues in theory and experiment.
Description of Current Research
My current research focuses on
precision measurements of fundamental importance in subatomic
Our group is engaged in a sub-ppm measurement of the muon's anomalous magnetic moment (g-2).
The results of this experiment, when compared with precise
theoretical calculations, are capable of revealing physics
beyond the Standard Model attributed to SUSY particles of high
mass, to structured intermediate vector bosons, or to
substructure of the muon
itself. Our final measurement, from the Brookhaven E821
Experiment, is more than 3 standard deviations from the current
(2010) Standard Model expectation and the result has caused a
significant buzz in the theoretical community. We are
promoting a new measurement at Fermilab
to achieve much high precision as the muon
anomaly remains an important low-energy test of new physics and
refining the result will be critical to aid in elucidating the
nature of any new physics scenarios revealed at the LHC.
Our group has been a leader in the detector development, the
beam delivery calculations and in the overall organization of
the experiment. We built a custom
W-scintillating-fiber electromagnetic calorimeter and are
testing and evaluating it at present. [Selected Readings here]
MuLan: The Muon Lifetime Analysis (MuLan) experiment measures the positive muon lifetime, which provides the most precise determination of the Fermi coupling constant, one of the fundamental inputs to the standard model. Recent advances in theory have reduced the theoretical uncertainty on the Fermi coupling constant as calculated from the muon lifetime to a few tenths of a ppm. The remaining uncertainty on the Fermi constant is entirely experimental and is dominated by the uncertainty on the muon lifetime. The MuLan experiment employs an innovative pulsed beam, a symmetric detector, and modern data-taking methods to reduce the uncertainty on the muon lifetime to 1 ppm. This experiment, just like the next two listed, takes place at the Paul Scherrer Institute, Switzerland. We recently completed data taking and analysis and achieved our exact proposal goal of 1.0 ppm final precision, measured twice in blind experiments. The Fermi constant, so obtained, has a precision of 0.6 ppm. Our PRL is in press. See this preprint now. The photo at the right shows some of us having prepared the soccer-ball-shaped detector for shipping to PSI.
MuCap: The goal of the MuCap experiment is a 1% precision measurement of the muon capture rate on the proton. From the capture rate, the pseudoscalar form factor, gP, of the nucleon will be extracted with 7% precision. This basic quantity is predicted theoretically with high precision, but the experimental situation is quite controversial. The first round of our experiment led to a first unambiguous value for gP and a strong confirmation of the chiral symmetry of QCD at low energies. The success was based on the novel idea of capturing negative muons in ultra-pure hydrogen gas (not liquid) and, equally importantly, instrumenting the stopping volume in the manner of a time projection chamber (TPC). My colleague Peter Kammel (now UW Research Professor) invented the idea and has led the effort from its inception. Two MuCap Ph.D. students were the co-winners of the APS Nuclear Physics Dissertation prize for this work. Meanwhile, we collected more than 10 times as much data and we are actively working on the analysis, with expected results in early 2011.
MuSun: This experiment, also led by Kammel, follows naturally on the development from MuCap and utilizes much of the same basic equipment. What is new is a cryogenic high-pressure deuterium TPC, operated in ionization mode, that can locate stopped muons and provide high resolution on the deposited energy. The motivation for md capture is based on measuring the rate of the semileptonic weak process μ + d --> n + n + νμ . The process can be described up to a low-energy constant (LEC) in various modern effective field theoris. Similarly, so can several similar fundamental reactions of astrophysics interest, such as solar pp fusion and the n+d reactions as observed by the SNO experiment. A precise measurement by MuSun will fix the common LEC and will therefore help, as theorists have stated, calibrate the sun. We have recently completed a first successful test run where a small physics data set has been obtained. In the next years, our UW group will focus effort on small hardware improvements, long data collection periods, and the detailed analysis.
Mu2e: The Mu2e Experiment at Fermilab is a major new effort for the laboratory that seeks to measure the Standard Model forbidden direct conversion of a muon to an electron (charged lepton flavor violation; cLFV) to a single event sensitivity below 1 part in 1016! There are many hints that cLVF should occur at this level, or else severe constraints will be placed on many popular SM extensions. The idea for the experiment has been around for a very long time; the realization, of course, is difficult. Now, Fermilab -- blessed by supportive external committees and the DOE -- is investing the R&D and funds to build the experiment. It requires a series of superconducting solenoids for the production, transport, and detection of muons and converted electrons. The Collaboration is in an active design phase with a timetable for first running not before about 2017 or 2018. Our group expertise on muon capture and calorimeter and other detector development fit nicely into the needs of Mu2e and we intend to be fully involved over the coming years. To date, we organized a muon capture test of candidate Al and Ti targets to measure critical ejected proton and neutrons, which will affect the detector design. We plan to continue these efforts in the coming years.