William D. Shephard

Professor Emeritus,
Elementary Particle Physics

Research Interests
Prof. Shephard's research in experimental elementary particle physics is carried out at Fermi National Accelerator Laboratory (Fermilab) and Brookhaven National Laboratory (BNL). This research is carried out by studying the particles produced in high energy interactions.

At Fermilab proton-antiproton collisions at the highest available energies are studied using the upgraded D0 detector. In these interactions, we are searching for evidence of new phenomena beyond the current Standard Model of elementary particle physics. In addition to searches for possible supersymmetric and Higgs particles we are also studying the properties of the known b and t quarks. Notre Dame played a major role in construction of the D0 central fiber tracker (CFT) and we continue work on operating, improving, and understanding the detector.

At BNL, partial wave analyses of specific final states are used to search for exotic mesons produced in pion-proton interactions observed in the Multi-Particle Spectrometer (MPS). Exotic mesons, whose internal structure differs from the normal quark-antiquark valence structure of mesons in the simple quark model, are expected to exist within the framework of quantum chromodynamics (QCD). Such mesons have been observed for the first time in our experiments and we are measuring their properties in order to obtain a deeper understanding of QCD, the theory of strong interactions.

Selected Publications:

“Exotic and qqbar resonances in the p⁺p^-p^- system produced in p^-p collisions at 18 GeV,” S.U. Chung et al., Phys. Rev. D65 072001, 1-16 (2002).

“Observation of exotic meson production in the reaction p^-p  ®   h ¢ p^-p at 18 GeV/c,” E.I. Ivanov et al., Phys. Rev. Lett. 86 , 3977-3980 (2001).

“Partial-wave analysis of the hp⁺p^-system produced in the reaction p^-p ® hp⁺p^-p at 18 GeV/c,” J.J. Manak et al., Phys. Rev. D62 012003, 1-8 (2000).

“A New Measurement of the Lifetime of the X⁺_c,” P.L. Frabetti et al., Phys. Lett . B 427 , 211-216 (1998).

Honors and Activities

Prof. Shephard has been a Fulbright senior research fellow at the Max Planck Institut fur Physik und Astrophysik, Munich, Germany, and a guest professor at the University of Nijmegen, Netherlands. He was the organizer of the XII International Symposium on Multiparticle Dynamics which was held at Notre Dame.

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