Roy A. Briere, Associate Professor Ph.D., University of Chicago Email: rbriere@andrew.cmu.edu Phone: (412) 268-2742 FAX: (412) 681-0648

My research field is high-energy particle physics. I am interested in "flavor physics" as well as other topics. The weak interaction has several unique features, including the violation of discrete symmetries such as parity (mirror reflection) and CP (combined parity and matter-antimatter inversion). In addition it is the only force which results in a change of particle type upon emission of one of its force carriers, the W boson. As such, it is responsible for all fundamental decays. Flavor physics is the study of the decays and other properties of the different types (or flavors) of quarks due to the weak interaction.

These interests stem from my Ph.D. research measuring CP violation and tests of CPT symmetry (CP plus reversal of time flow) in the neutral K meson system (K mesons contain strange quarks). Since my dissertation, I have been a member of the CLEO collaboration. We study electron-positron interaction data at CESR (the Cornell Electron Storage Ring) with the CLEO detector ("CLEOpatra & CESR"). CLEO pioneered many aspects of B meson physics; these particles contain the bottom (or beauty) quark. Recently, the advent of dedicated B factories at SLAC and KEK has led CLEO to lower (!) its energy to the charm threshold region and we are now the world's premier charm quark physics experiment, known as CLEO-c. We study mesons with charm quarks, such as the D+, D0, Ds, and psi(2S). Many key measurements needed for progress in flavor physics, such as decay constants, semileptonic form factors, and absolute hadronic branching ratios, are already measured best with CLEO-c's pilot-run data. Of course, the range of physics topics at CLEO remains broad. In addition to charm, and past work with bottom, I am also pursuing studies of Upsilon resonance decays and two-photon physics. In July, 2005 I began two-years as the elected co-spokesperson of CLEO (with Prof. E.H. Thorndike of the Univ. of Rochester).

Future plans after CLEO include work on the CMS detector at the LHC, along with Profs. Ferguson and Vogel, who are also collaborators on CLEO.

Selected Publications

D.M. Asner et al., "Anti-Deuteron Production in Upsilon(nS) Decays and the Nearby Continuum", Phys. Rev. D 75, 012009 (2007).

Q. He et al. (CLEO Collaboration), "Measurement of Absolute Hadronic Branching Fractions of D Mesons and e+e- --> D Dbar Cross Sections at E_cm = 3773 MeV", Phys. Rev. Lett. 95, 121801 (2005).

G.S. Huang et al. (CLEO Collaboration), "Study of the Semileptonic Charm Decays D^0 --> pi- l+ nu and D0 --> K- l+ nu" Phys. Rev. Lett. 94, 011802 (2005).

S.E. Csorna et al. (CLEO Collaboration), "Measurements of the Branching Fractions and Helicity Amplitudes in B -> D* rho Decays", Phys. Rev. Lett. D 67, 112002 (2003).

R.A. Briere et al., "CLEO-C and CESR-C: A New Frontier of Weak and Strong Interactions", CLNS-01-1742 (2001).

Roy Briere, "Tracking in He-Based Gases: Present and Future Factories", Heavy Flavor Physics, (C.Campagnari, ed.), p. 442.

Roy A. Briere and Bruce Winstein, "Determining the Phase of a Strong Scattering Amplitude from its Momentum Dependence to better than 1-degree: The Example of Kaon Regeneration", Phys. Rev. Lett. 75, 402 (1995), E: 75, 2070 (1995).