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193The electromagnetic inelastic form factors of ep.....o;eN* are calculated in a covariant way, on the basis of a relativistic extended-particle model introduced as a straight-forward extension of the nonrelativistic quark model. It is shown that the inelastic form factors have the same q2-dependence as the elastic one at higher momentum transfers, that is,for q2 larger than the nucleon mass. This theoretical result, coming mainly from the Lorentz contraction of the nucleon as an extended particle, is consistent with recent experiment.The nucleon elastic form factors are also discussed in the same framework of the model. In particular it is shown that the neutron electric form factor appearing as a relativistic effect is consistent with existing experimental data. of N* (or N), Nand photon, respectively. For q 2 > M 2 (M being the nucleon mass), that is, lqi?: M, one of N* (or N) and N or both should be relativistic.Observing the vertex in the rest system of the N*, for instance, we have the relativistic initial nucleon with momentum P 1 = -q and Lorentz factor rz

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The ␣ϩ 6 He elastic scattering is investigated within a microscopic multicluster model, involving a realistic description of the 6 He halo nucleus. Phase shifts and elastic-scattering cross sections are calculated up to E c.m. ϭ15 MeV with two variants of the resonating-group method. The model gives rise to 1 Ϫ and 3 Ϫ molecular states near E c.m. ϭ0.5 MeV and E c.m. ϭ3.7 MeV, respectively. We suggest that the broad 3 Ϫ resonance should be observable by comparing elastic cross sections at different energies. We also evaluate the order of magnitude of the 6 He breakup cross section. ͓S0556-2813͑99͒03902-3͔

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