FIZIKA B 13 (2004)  1, 251-264

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COHERENCE LENGTH AND NUCLEAR SHADOWING FOR TRANSVERSE AND LONGITUDINAL PHOTONS

JÍRG RAUFEISEN

Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
E-mail address: jorgr@lanl.gov

Received 1 August 2003;     Accepted 24 May 2004
Online 10 October 2004

We study nuclear shadowing for transverse and longitudinal photons. The coherence length, which controls the onset of nuclear shadowing at small Bjorken-x, xBj, is longer for longitudinal than for transverse photons. The light-cone Green function technique properly treats the finite coherence length in all multiple scattering terms. This is especially important in the region xBj>0.01, where most of the data exist. NMC data on shadowing in deep inelastic scattering are well reproduced in this approach. We also incorporate nonperturbative effects, in order to extrapolate this approach to small photon virtualities Q2, where perturbative QCD cannot be applied. This way, we achieve a description of shadowing that is based only on quark and gluon degrees of freedom, even at low Q2.

PACS numbers: 13.60.-r, 12.40.Vv, 25.30.Mr
UDC 539.12.14

Keywords: nuclear shadowing, photons, light-cone Green function technique, deep inelastic scattering

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