Nimai C. Mukhopadhyay

Nuclear Muon Capture

This report attempts to survey our present knowledge of the nuclear muon capture reactions. Starting from the formation of the muonic atom, various phenomena, having a bearing on the nuclear capture, are reviewed. The nuclear reactions are then studied from two angles — to learn about the basic muon-nucleon weak interaction process, and to obtain new insights on the nuclear dynamics. Future experimental prospects with the newer generation muon “factories” are critically examined. Possible modification of the muon-nucleon weak interaction in complex nuclei remains the most important open problem in this field.

Photoproduction of the eta-prime mesons as a new tool to probe baryon resonances

We examine {eta}{prime} photoproduction as a novel tool to study baryon resonances around 2 GeV, of particular interest to the quark shell model, which predicts a number of them. We find important roles of the form factors at the strong vertices, and show that the {ital N}{sup *}(2080) can be probed efficiently by this reaction.

Role of theD13(1520)resonance inηelectroproduction

We investigate the electroproduction of eta mesons below a center of momentum energy of 1.6 GeV, with particular emphasis on the roles of the N*(1535) and N*(1520) resonances. Using the effective Lagrangian approach, we show that the transverse helicity amplitude of the N*(1535) can be extracted with good accuracy from the new eta electroproduction data, under reasonable assumptions for the strength of the longitudinal helicity amplitude. In addition, although the differential cross section is found to to have a small sensitivity to the N*(1520) resonance, it is shown that a recently completed double polarization experiment is very sensitive to this resonance.