Gerhard Graw

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The HERMES experiment is collecting data on inclusive and semi-inclusive deep inelastic scattering of polarised positrons from polarised targets of H, D, and He. These data give information on the spin structure of the nucleon. This paper describes the forward angle spectrometer built for this purpose. The spectrometer includes numerous tracking chambers(More)
Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for(More)
A. Airapetian,32 N. Akopov,32 M. Amarian,24,27,32 E. C. Aschenauer,13,14,6 H. Avakian,10 R. Avakian,32 A. Avetissian,32 E. Avetissian,10,32 B. Bains,15 C. Baumgarten,22 M. Beckmann,12 S. Belostotski,25 J. E. Belz,28,29 Th. Benisch,8 S. Bernreuther,8 N. Bianchi,10 J. Blouw,24 H. Böttcher,6 A. Borissov,6,14 M. Bouwhuis,15 J. Brack,4 S. Brauksiepe,12 B.(More)
and the Observation of Relaxation Processes B. Brauna, E. M. Gabrielb, H. G. Gaulb , G. Grawa, H. Kolstera, A. Metza, K.Reinm} ullera, P. Schiemenza, I. Simiantonakisb, E. Ste ensb aSektion Physik, Universit} at M} unchen, 85748 Garching, Germany bMPI f} ur Kernphysik, 69029 Heidelberg, Germany now at SAP, 69190 Walldorf, Germany Abstract. This contribution(More)
Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per(More)
A. Airapetian,31 N. Akopov,31 Z. Akopov,31 M. Amarian,26,31 E. C. Aschenauer,7 H. Avakian,11 R. Avakian,31 A. Avetissian,31 E. Avetissian,31 P. Bailey,15 B. Bains,15 V. Baturin,24 C. Baumgarten,21 M. Beckmann,12 S. Belostotski,24 S. Bernreuther,29 N. Bianchi,11 H. Böttcher,7 A. Borissov,6,19 O. Bouhali,23 M. Bouwhuis,15 J. Brack,5 S. Brauksiepe,12 W.(More)
The dependence on Q (the negative square of the 4-momentum of the exchanged virtual photon) of the generalised Gerasimov-Drell-Hearn integral for the proton has been measured in the range 1.2 GeV < Q < 12 GeV by scattering longitudinally polarised positrons on a longitudinally polarised hydrogen gas target. The contributions of the nucleon-resonance and(More)
The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the(More)
Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin(More)