A partial-wave analysis of single-pion photoproduction data has been completed. This study extends from threshold to 2 GeV in the laboratory photon energy, focusing mainly on the influence of new measurements and model dependence in the choice of parametrization employed above the two-pion threshold. Results are used to evaluate sum rules and estimate resonance photodecay amplitudes. These are compared to values obtained in the MAID analysis.

A partial-wave analysis (PWA) of $\mathrm{NN}$ elastic scattering data has been completed. This analysis covers an expanded energy range, from threshold to a laboratory kinetic energy of 3 GeV, in order to include recent elastic $\mathrm{pp}$ polarized scattering measurements performed at SATURNE II. Results of the energy-dependent fit are compared with single-energy solutions and Saclay amplitudes obtained via the direct-reconstruction approach. We also comment on the status of ${\epsilon }_1$ in the low-energy region.

An energy-dependent and set of single-energy partial-wave analyses of NN elastic scattering data have been completed. The fit to 1.6 GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of πNN coupling constant. We also comment on the possibility of fitting np data alone. These results are compared with those found in the recent Nijmegen analyses.

We present results from a comprehensive partial-wave analysis of ${\pi }^{\pm }p$ elastic scattering and charge-exchange data, covering the region from threshold to $2.1\text{GeV}$ in the lab pion kinetic energy, employing a coupled-channel formalism to simultaneously fit ${\pi }^{-}p\to \eta n$ data to $0.8\text{GeV}$. Our main result, solution FA02, utilizes a complete set of forward and fixed-$t$ dispersion relation constraints, from threshold to $1\text{GeV}$, and from $t=0$ to $-0.4{(\text{GeV}∕c)}^2$, applied to the $\pi N$ elastic amplitude. A large number of systematic checks have been performed, including fits with no charge-exchange data and other database changes, fits with few or no dispersion relation constraints, and changes to the Coulomb correction scheme. We have also reexamined methods used to extract Breit-Wigner resonance parameters. The quality of fit to both data and dispersion relation constraints is superior to our earlier work. The results of these analyses are compared with previous solutions in terms of their resonance spectra and preferred values for couplings and low-energy parameters, including the $\pi NN$ coupling constant.

The photoproduction of the $$J/\psi $$J / ψ off the proton is believed to deepen our understanding of various physics issues. On the one hand, it is proposed to provide access to the origin of the proton mass, based on the QCD multipole expansion. On the other hand, it can be employed in a study of pentaquark states. The process is usually assumed to proceed through vector-meson dominance, that is the photon couples to a $$J/\psi $$J / ψ which rescatters with the proton to give the $$J/\psi p$$J / ψ p final state. In this paper, we provide a compelling hint for and propose measurements necessary to confirm a novel production mechanism via the $$\varLambda _c \bar{D}^{(*)}$$Λ c D ¯ ( ∗ ) intermediate states. In particular, there must be cusp structures at the $$\varLambda _c \bar{D}^{(*)}$$Λ c D ¯ ( ∗ ) thresholds in the energy dependence of the $$J/\psi $$J / ψ photoproduction cross section. The same mechanism also implies the $$J/\psi $$J / ψ -nucleon scattering lengths of order 1 mfm. Given this, one expects only a minor contribution of charm quarks to the nucleon mass.

The $K^{+}$-nucleon elastic scattering process has been reexamined in light of recent measurements which have found a narrow exotic $S=+1$ resonance in their $KN$ invariant mass distributions. We have analyzed the existing database in order to consider the effect of a narrow state on fits to $K^{+}$-nucleon observables.