Professor Sau Lan Wu

Enrico Fermi Professor of Physics
Vilas Professor

University of Wisconsin-Madison


The compelling desire of PI Sau Lan Wu’s research group is to produce exciting physics results i.e. our primary motivation is physics discovery. Based upon this guiding principle, our main topics of research are those with great discovery potential. Wu started this task in 1977 when she joined Wisconsin as an assistant professor.  In her career so far, she has participated in three major discoveries, in two of which she played a leading role, the gluon and the Higgs boson.

(1) Discovery of the Charm Quark in 1974. As a post-doc at MIT, she was one of the very active participants of the experiment that led to the discovery of the J/ψ particle at Brookhaven, first evidence of the charmed quark. For this discovery, her supervisor, Professor Samuel Ting, shared the 1976 Nobel Prize with Professor Burton Richter.

(2) Discovery of the Gluon in 1979. Wu was the leading figure in the gluon discovery via three-jet events in the TASSO experiment at DESY. Her work led to sharing, with three DESY physicists (P. Söding, B. Wiik, and G. Wolf), of the 1995 High Energy and Particle Physics Prize of the European Physical Society “for the first evidence for three-jet events in e+ecollisions at PETRA,” which was the first direct observation of the gluon. She was chosen among the four recipients to address in the award ceremony. In 1996, Wu was elected Fellow of the American Academy of Arts and Sciences.

(3) Discovery of the Higgs Boson in 2012. Wu and her Wisconsin group played a leading and outstanding role in the discovery of the Higgs Boson: in the Hγγ H→ZZ→4 leptons and the Higgs combination effort. We have been among the major contributors and were among the first groups to obtain the five sigma observation, which contributed to the CERN announcement on July 4, 2012 of the discovery of a particle at ~125 GeV, now confirmed to be the Higgs boson.

PHYSICS PROGRAM. Following the very successful physics programs in the TASSO experiment at PETRA, DESY (1977-1989), the ALEPH experiment at LEP, CERN (1980-2001), and the BaBar experiment, SLAC (1995-2007), the present activities of our group have been in the ATLAS experiment at LHC (1993-present), focusing on the Higgs discovery. Our group was the first U.S. group to join ATLAS. For 18 years until 2010 we worked on our Silicon Readout Drive effort, our High Level Trigger effort, software development and physics preparation for Higgs searches. Finally, our hard work bears fruit – we have the Higgs discovery.