Effective Theories Of The Strong Interaction

Abstract

This is the final report corresponding to the full funding period (08/01-07/04) in the Department of Energy Outstanding Junior Investigator Grant DE-FG03-01ER41196. The development of an understanding of the interplay between perturbative and non-perturbative effects in strong-interacting systems forms the broad context of this research. The main thrust is the application of effective theories to QCD. Topics included a new power counting in the pionful effective theory, low-energy Compton scattering, charge-symmetry breaking in pion production and in the two-nucleon potential, parity violation, coupled-channel scattering, shallow resonances and halo nuclei, chiral symmetry in the baryon spectrum, existence of a tetraquark state, and molecular meson states. DOE grant DE-FG03-01ER41196 was used to partially support in the period 08/01-07/04 the research activities of the Principal Investigator, Dr. Ubirajara van Kolck, one post-doctoral research associate, Dr. Boris A. Gelman, and one graduate student, Mr. Will Hockings. During the grant period the PI was first Assistant then Associate Professor of Physics at the University of Arizona (UA), and a RHIC Physics Fellow at the RIKEN-BNL Research Center (RBRC). The association with RBRC ended in the Summer of 2004. Since September of 2002 the PI has also been partially supported by a Sloan Research Fellowship. Dr. Boris Gelman was supported by the grant from September 2002 to May 2004. He joined the UA after receiving a Ph.D. from the University of Maryland in the Summer of 2002. He left to take a research associate position in the nuclear theory group of the State University of New York at Stony Brook. The support of a post-doctoral researcher on this grant for two years was only possible by carrying over first- and second-year funds to later years. In addition, Mr. William Hockings started doing research under the PI's guidance. Mr. Hockings took Independent Study courses with the PI, while working as a teaching assistant in the UA Department of Physics. He learned the basic ideas of non-relativistic effective field theories, such as ''reparametrization'' invariance, and studied a simple application of effective field theory to Compton scattering on the nucleon at energies well below the pion mass. Mr. Hockings has passed the qualifying exam (called ''comprehensive'' at UA) with a solid performance, and is now pursuing a Ph.D. in nuclear physics, supported by the grant. Grant activities are described in Sect. 2. They included the publication of research papers, the delivery of seminars and lectures, and the organization of scientific meetings and (together with UA colleagues) of a series of local seminars, as listed in the Appendix.