<p> Experimental and theoretical investigations on charge dependence and charge asymmetry in N-N and λ-N interactions are reviewed. The γ-π-exchange N-N and λ-N potentials are derived and calculated in the static limit. The γ-π-exchange charge dependent component of the N-N potential is found to be larger than the charge dependent part of OPEP due to pion mass difference up to 3 fm and is of opposite sign, making the explanation of the splitting between p-n and p-p scattering lengths more difficult than was previously thought. Except at very short distances, this potential is of the order of only a few percent of the OPEP. In the light of this result, it is concluded that the very large charge-dependent correction at large distances required by Noyes' phenomenological analysis on the splitting of rpn and rpp is inexplicable as an electromagnetic correction. The γ-π exchange charge asymmetric components of both N-N and λ-N interactions are found to be much weaker than the charge dependent one for the N-N case.</p> / Thesis / Doctor of Philosophy (PhD)

We have measured the flavor dependence of multiplicities for $\\pi^+$ and $\\pi^-$ production in semi-inclusive deep-inelastic scattering (SIDIS) on proton and deuteron targets. We used a 10.6 GeV electron beam at Jefferson Lab, and 4 msr solid angle spectrometers (HMS for electrons, SHMS for pions), the lepton vertex spanned the kinematic range $0.3 < x < 0.6$, $2 < Q^2 < 5$ GeV$^2$, and $4 < W^2 < 11$ GeV$^2$. The pion fractional momentum range was $0.3 < z < 0.7$ and the small transverse momentum range was $0 < P_t < .25$ GeV. We used the multiplicities to form sum-and-difference ratios, testing the validity of factorization. We extracted two favored and two unfavored $W$ dependent fragmentation functions (FFs) from these multiplicities. Assuming factorization at low $P_t$, we find that the two ``favored" FFs allow for isospin breaking (charge symmetry violation) at low $W$, while converging to a common value at the highest $W$ of this experiment. The two unfavored FFs are consistent with each other within the experimental uncertainties.

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