The ALEPH Experiment

The ALEPH experiment is exploring the high energy frontier of electron-positron collisions. It is based at the LEP storage ring at the CERN laboratory in Geneva, Switzerland. Electrons are collided against positrons at 200 GeV in the center of mass, the highest e+e- energies ever achieved. This energy is sufficient to produce pairs of W and Z gauge bosons (the carriers of the weak force), and to make precision measurements of their properties. It is hoped that this energy is also sufficiently high to produce the Higgs boson, the "Holy Grail" of particle physics, and possibly Supersymmetric partners of the Standard Model particles. The hunt for physics beyond the Standard Model is definitely on!

The SCIPP group is based at CERN and is thus very actively engaged in the experimental program. Our physics interests are in the fields of B physics (where we have studied decays of interest for evidence of CP violation), and the search for new particles (including the Higgs boson and Supersymmetric particles) and new phenomena at these high energies. We are studying single and multiphoton final states which play a key role in the search for various forms of invisible, or almost invisible, matter, and in the study of the electroweak interaction and the pointlike nature of the electron at distances down to 10^-16 cm. Recently, the group initiated an effort to search for the effects of quantum gravity in models which incorporate large extra spatial dimensions (beyond the three we are already familiar with). The SCIPP/ALEPH group has now made measurements related to all four forces in Nature: strong, electromagnetic, weak, and gravitational.

The SCIPP group also plays a key role in the operation of the detector, particularly with respect to the silicon vertex detector. The precision tracking capability of the vertex detector is critical for the detection of jets containing b-quarks, and is therefore vital in the search for the Higgs boson, which is expected to decay a large fraction of the time into b anti-b jets.

SCIPP contact: Alan Litke