Medium energy physics concentrates on the non-perturbative regime of quantum chromodynamics (QCD). In this regime, advances tend to be driven by experimental data, one source of which is the spectrum of hadrons, both mesons and baryons. In particular, the search for so called exotic hadrons, those which exhibit gluonic degrees of freedom is currently a very important experimental and theoretical topic. In order to distinguish this exotic matter from the normal hadronic matter, it is important to make very complete studies. Information such as particle masses, quantum numbers, decay modes and production mechanisms are important inputs to the puzzle.

My recent work involved the the Crystal Barrel detector at the Low Energy Antiproton Ring at CERN. This detector is a nearly 4pi solid angle apparatus for studying objects formed in proton antiproton annihilations at rest, and in flight. A major emphasis of our program is to look for exotic forms of hadronic matter in particular glueballs (only gluons) and hybrids mesons (quarks and gluons). The proton antiproton annihilation is considered a gluon-rich environment which could produce these exotic mesons. They then decay into mesons that are detected in the experiment. After many years of study, we have found a particle which is a very good candidate for the ground state glueball. Data analysis is currently finishing up on this experiment, with the last phases of this experiment concentrating on important decay channels, as well as the production mechanism itself.

If Crystal Barrel has found the ground state glueball, then this opens up a host of questions on both normal matter, and hybrid mesons. Many of these questions can be answered by experiments which will be performed at a new accelerator, CEBAF at the Jefferson Lab in Newport News, Virginia. We will start to understand some of these issues with the current generation of CEBAF experiments, in particular the CLAS experiment which is taking data now. However, the real information will come out of an experiment which is currently in the research and development stage, the Hall D effort. This experiment will involve a new hall with a spectrometer designed and built to do meson spectroscopy in photo production. I think that with this program, we have an excellent opportunity to resolve many of the key issues in QCD, particularly this issue of confinement.

My current College of Science Annual Report.

Selected Publications 

H. Denizli et al. (CLAS Collaboration), “dependence of the  (1535) photocoupling and evidence for a P-wave resonance in eta electroproduction”, Phys. Rev. C76, 015204, (2007).

T. Mibe et al. (CLAS Collaboration), “First measurement of coherent phimeson photoproduction on deuteron at low energies”, Phys. Rev. C76, 052202, (2007).

L. Guo et al. (CLAS Collaboration), “Cascade production in the reactions and ” Phys. Rev. C76, 025208, (2007).

I. Hleiqawi et al. (CLAS Collaboration), “Cascade production in the reactions  reaction at .” Phys. Rev. C75, 042201, (2007), Erratum-ibid. C76, 039905, (2007).

K.S. Egiyan et al. (CLAS Collaboration), “Experimental study of exclusive  reaction mechanisms at high ”, Phys. Rev. Lett. 98, 262502, (2007).