Higgs Physics 

At present, all the data obtained from the many experiments in particle physics are in agreement with the Standard Model.  In the Standard Model, there is one particle, the Higgs particle, that is responsible for giving masses to all the particles with mass.  In this sense, the Higgs particle occupies a unique position.

Our group has been very active in Higgs searches for the past 20 years (see invited talks of Prof. Sau Lan Wu).

Before the later part of the year 2000, the Higgs particle was not observed experimentally.  After the center-of-mass energy at the LEP accelerator of CERN reached 205 GeV in 2000, excess candidates began to show up in the standard model Higgs analysis.  See ALEPH paper, Observation of an Excess in the Search for the Standard Model Higgs Boson at ALEPH Physics Letters B495 (2001) 1. These candidates are most naturally explained by the production process:

e⁺e^- --> HZ --> four jets

This gives the first possible evidence for the Higgs particle.  The Wisconsin group in ALEPH was instrumental in finding the three most signal-like events from the four LEP experiments.    

On the basis of this possible evidence and related events, the mass of the Higgs particle has been determined to be around 115 GeV/c².  For a recent review on Higgs searches by Prof. Sau Lan Wu and Peter McNamara, see Higgs Particle in the Standard Model:  Experimental Results from LEP Reports on Progress in Physics 65 (April 2002) 465.

One of the most exciting prospects for the LHC is confirming or contradicting this first possible evidence for the Higgs particle.  The hope is therefore to collect hundreds or thousands of Higgs events with an accurate determination of its mass.  Although the QCD backgrounds are expected to be large, the LHC, with its high energy and luminosity, is the ideal accelerator to study the Higgs.