Work supported in part by BMBF
Nuclear quark and gluon distributions in coordinate space
M. Vänttinen1 - G. Piller1 - L. Mankiewicz1,2 - W. Weise1 - K.J. Eskola3
1 Physik Department, Technische Universität München, D-85747 Garching, Germany
2 N. Copernicus Astronomical Center, Polish Academy of Science, Warsaw
3 Department of Physics, University of Jyväskylä, P.O.Box 35, FIN-40351 Jyväskylä,
Finland
Received: 17 August 1998 / Revised version: 25 September 1998 Communicated by A. Schäfer
Abstract
In coordinate space, quark and gluon distributions of the nucleon
are defined as correlation functions involving two field operators
separated by a light-cone distance y+ = 2l. We study the nuclear
modifications of these distributions. The largest effect
is a strong depletion of parton distributions (shadowing) at large
longitudinal distances, which starts
for all parton species at l=2 fm, i.e. at the average
nucleon-nucleon separation in nuclei. On the other hand, the nuclear radius
does not play a significant role.
At 
fm, nuclear modifications of parton distributions
are small. The intrinsic structure of individual nucleons is
evidently not very much affected by nuclear binding. In particular,
there is no evidence for a significant increase of the quark or
gluon correlation length in bound nucleons.
PACS
13.60.Hb Total and inclusive cross sections -
14.20.Dh Protons and neutrons -
24.85.+p Quarks, gluons, and QCD in nuclei and nuclear processes
Copyright Springer-Verlag
