Heavy Quark Physics at Babar

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

Funds are requested to support the research of two professors at the University of Cincinnati. The research effort is concentrated at the Stanford Linear Accelerator Center (SLAC) and makes use of the BaBar detector facility. The BaBar detector was built by a large international collaboration including the PIs and has been in continuous use for the past five years. The principal scientific goal of the BaBar experiment is the study of CP violation, an important ingredient in the particle-antiparticle asymmetry of the universe, and its relationship with the Standard Model (SM) describing interactions between elementary particles. In particular, the SM predicts that measurement of various decays of B mesons can be related through the 3x3 Cabbibo-Kobayaski-Maskawa (CKM) matrix. The phases in this matrix are related through a unitarity triangle whose three angles, alpha, beta, and gamma, should sum to 180 degrees. The BaBar experiment uses the PEP2 accelerator at SLAC, which was designed to provide a large number of B mesons. The high B meson flux makes it possible to examine many rare decay modes that are suitable for measurement of each of the mixing angles. The experiment has also produced other interesting physics results, including the surprising discovery of new strange, charmed mesons (DsJ ) with unusual properties. The PIs were directly involved in this discovery. The Cincinnati group proposes to carry out analyses aimed at measurement of the angle, gamma, and at other investigations of importance in the study of B and D mesons and other heavy quark systems. These studies will include a search for phenomena such as mixing in the neutral D system that may involve physics beyond the SM. The BaBar experiment runs in a so-called factory mode, which is a requirement for producing the large number of B mesons needed. This mode of running mandates that all members of each university group work on significant service tasks. The Cincinnati group works largely on the DIRC - a novel particle identification device. Both BaBar and PEP2 are working well. PEP2 is running at levels that significantly exceed its design specifications. In its broader impacts, this proposal will contribute to the education of the students and postdoctoral associates in the Cincinnati group. They are exposed to a great deal of up-to-date technology, in addition to being trained in a closely watched environment in elementary particle physics. Based at SLAC, their efforts are on view to a large community of important physicists who are found there. They become highly skilled in computing in various environments, in the diagnosis of electronic and mechanical systems, and in presentation of results and ideas in the almost daily meetings required of a large collaboration.