Lattice Field Theory and Hadronic Physics

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Considerable theoretical progress combined with enormous advances in computertechnology has made lattice .eld theory a powerful tool in the study ofnuclear and sub-nuclear structure. The proposed activity has the following intellectualmerits: i) proposal of new ideas and exploration of new theoreticalapproaches to compute interesting novel physical quantities; ii) use of existingtechniques along with state-of-the-art computers to obtain results of experimentalinterest.Calculations in lattice QCD are often performed in the quenched approximation.Quenching e.ects will be studied in detail using lattice fermions thathave exact chiral symmetry. Calculations beyond the quenched approximationare computationally intensive and planar QCD will be studied to see if it is aphysically viable alternative.Exotic hybrid mesons contain valence gluons and can only be studied properlyin the framework of QCD. Experiments scheduled in Hall D at JLab planto look for such exotic hybrid mesons. Computations of their decay widths willbe performed to provide some guidance for the experimental searches of theseexotic hybrids.Lattice QCD will be used to study nuclear forces present in a two hadronsystem. It will also be used to study the electric and magnetic polarizabilities ofhadrons. These computations are technically involved and results would considerablyincrease our understanding of nuclear interactions from .rst principles.Chiral symmetry in QCD is spontaneously broken at low temperatures butit is expected to get restored at high temperatures. QCD at high temperaturesis described by a quark-gluon plasma. The physics around the chiral phasetransition will be investigated using lattice QCD with chiral fermions. The roleof instantons at .nite temperature will be carefully studied.The proposed research will greatly bene.t from the participation of a fulltimepostdoctoral fellow and a graduate student. The graduate student workingin close association with the PIs and the postdoctoral fellow will become familiarwith the research done at the forefront of nuclear theory and also get a goodtraining in the use of state-of-the-art parallel computing resources. As part ofthe outreach program, a senior physics student will be employed to set up awebsite describing the projects at a level that is accessible to high school students,teachers and the local community at large. By focusing on high pro.letopics currently of great interest at national laboratories, the proposal hopes toassist in the e.orts of the local university to attract new students from underrepresentedgroups.