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Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function ~(x, Q2) in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized 3He internal gas target. The data cover the kinematic range 0.023 < x < 0.6 and 1 (GeV/c) 2 < Q2 < 15 (GeV/c) 2. The integral fo~i0623 ~(x) dx evaluated at a fixed Qz of 2.5 (GeV/c) 2 is-0.0344-0.013(stat.)+0.005(syst.). Assuming Regge behavior at low x, the first moment F'~ = fl ~(x)dx is-0.037 ± 0.013(stat.)±0.005(syst.)±0.006(extrapol.

Cross sections for the reactions Mn(n, p), Fe(n, p), and Ni(n, p) have been measured at an incident energy of 198 MeV, with protons observed over a range of energies corresponding to excitations of up to about 35 MeV in the residual nuclei Cr, Mn, and Co, respectively. Measurements were carried out at center-of-mass angles between 1. 6' and 19. 9'. A multipole analysis of the results yielded the distribution of Gamow-Teller (GT) and spin-dipole strength for each target. The total GT strength below an excitation energy of 8.5 MeV was 1.? units for Mn, 2.9 units for Fe, and 3.8 units for Ni. Shell model calculations of the GT strength distribution, carried out in a restricted vector space, show fair to good agreement with the data up to an excitation energy of 8.5 MeV, but overestimate the total strength by a factor of between 3 and 4.

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We have set limits on contributions of scalar interactions to nuclear beta decay. A magneto-optical trap provides a localized source of atoms suspended in space, so the low-energy recoiling nuclei can freely escape and be detected in coincidence with the beta. This allows reconstruction of the neutrino momentum, and the measurement of the beta-nu correlation, in a more direct fashion than previously possible. The beta-nu correlation parameter of the 0(+)-->0(+) pure Fermi decay of (38)K(m) is a =0.9981+/-0.0030+0.0032 / -0.0037, consistent with the standard model prediction a =1.

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Spin transfer in deep-inelastic ⌳ electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the DESY HERA storage ring. For an average fractional energy transfer ͗z͘ϭ0.45, the longitudinal spin transfer from the virtual photon to the ⌳ has been extracted. The spin transfer along the ⌳ momentum direction is found to be 0.11Ϯ0.17(stat)Ϯ0.03(syst); similar values are found for other possible choices for the longitudinal spin direction of the ⌳. This result is the most precise value obtained to date from deep-inelastic scattering with charged lepton beams, and is sensitive to polarized up quark fragmentation to hyperon states. The experimental result is found to be in general agreement with various models of the ⌳ spin content, and is consistent with the assumption of helicity conservation in the fragmentation process.