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Register a new userMedium effects in K^+ nuclear interactions
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E. Friedman Hebrew U. Jerusalem
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Total and reaction cross sections are derived self consistently from the attenuation cross sections measured in transmission experiments at the AGS for K^+ on Li^6, C, Si and Ca in the momentum range of 500-700 MeV/c by using a V_{opt}=t_{eff}(rho)rho optical potential. Self consistency requires, for the KN in-medium t matrix, that Im t_{eff}(rho) increases linearly with the average nuclear density in excess of a threshold value of 0.088+-0.004 fm^-3. The density dependence of Re t_{eff}(rho) is studied phenomenologically, and also applying a relativistic mean field approach, by fitting the integral cross sections. The real part of the optical potential is found to be systematically less repulsive with increasing energy than expected from the free-space repulsive KN interaction. When the elastic scattering data for Li^6 and C at 715 MeV/c are included in the analysis, a tendency of Re V_{opt} to generate an attractive pocket at the nuclear surface is observed.
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An accurate description of the nuclear response functions for neutrino scattering in the Gev region is essential for the interpretation of present and future neutrino oscillation experiments. Due to the close similarity of electromagnetic and weak scattering processes, we will review the status of the scaling approach and of relativistic modeling for the inclusive electron scattering response functions in the quasielastic and $Delta$-resonance regions. In particular, recent studies have been focused on scaling violations and the degree to which these imply modifications of existing predictions for neutrino reactions. We will discuss sources and magnitude of such violations, emphasizing similarities and differences between electron and neutrino reactions.
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