van den J.F.J. Brand

Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle straight phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinstraight phi moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.

Measurement of the spin asymmetry in the photoproduction of pairs of high-pT hadrons at HERMES

We present a measurement of the longitudinal spin asymmetry A|| in photoproduction of pairs of hadrons with high transverse momentum pT. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h^+h^- pairs with _(pT)^(h1)>1.5GeV/c and _(pT)^(h2)>1.0GeV/c, the measured asymmetry is A_(||) = -0.28±0.12(stat)±0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization.

Proton ground-state correlations in 40Ca studied with the reaction 40Ca(e, e′ p)49K

The spectral function of the reaction 40Ca(e, e′ p)39K was measured with special emphasis on the knockout of protons from the 1f7/2 and 2p3/2 orbits above the Fermi level. Particularly for the transition to the 3/2− state two-step processes were found to be not negliglible. The spectroscopic strength for the 1f and 2p knockout, integrated up to 10 MeV excitation energy, is much less than the missing strength in the 1d3/2 and 2s1/2 orbits, but it agrees with values expected from calculations involving ground-state correlations.

Nuclear effects on R = sigma(L)/sigma(T) in deep-inelastic scattering.

This erratum revokes the main conclusion of a Letter that reported measurements of cross sections for deep-inelastic scattering (DIS) of leptons on

Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion ekectroproduction.

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Study of the mechanism of the reaction 4He(e,e'p)3H.

He and

(e,e'p) study of triton + deuteron + proton clustering in 6Li

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K+K- lifetime

N targets, expressed as ratios of

J/psi K-S(0) branching fraction

\sigma_A / \sigma_D

D K-+/- decays

to the cross section on the deuterium target.Cross section ratios for deep-inelastic scattering from 14N and 3He with respect to 2H have been measured by the HERMES experiment at DESY using a 27.5 GeV positron beam. The data cover a range in the Bjorken scaling variable x between 0.013 and 0.65, while the negative squared four-momentum transfer Q2 varies from 0.5 to 15 GeV2. The data are compared to measurements performed by NMC, E665, and SLAC on 4He and 12C, and are found to be different for x<0.06 and Q2<1.5 GeV2. The observed difference is attributed to an A-dependence of the ratio R=σL/σT of longitudinal to transverse deep-inelastic scattering cross sections at low x and low Q2.This erratum revokes the main conclusion of a Letter that reported measurements of cross sections for deep-inelastic scattering (DIS) of leptons on