Consistent treatment of charm evolution in deep inelastic scattering
A.D. Martin1 - R.G. Roberts2 - M.G. Ryskin1,3 - W.J. Stirling1,4
1 Department of Physics, University of Durham,
Durham, DH1 3LE, UK
2 Rutherford Appleton Laboratory, Chilton,
Didcot, Oxon, OX11 0QX, UK
3 Laboratory of
Theoretical Nuclear Physics, St. Petersburg Nuclear Physics
Institute, Gatchina, St. Petersburg 188350, Russia
4 Department of Mathematical Sciences, University of
Durham, Durham, DH1 3LE, UK
Received: 12 May 1997 / Revised version: 12 June 1997
Abstract
We present a formulation which allows heavy quark 
mass effects to be explicitly incorporated in both the
coefficient functions and the splitting functions in the parton
evolution equations. We obtain a consistent procedure for
evolution through the threshold regions for 
and
production in deep inelastic scattering, which
allows the prediction of the charm and bottom quark densities.
We use the new formulation to perform a next-to-leading order
global parton analysis of deep inelastic and related hard
scattering data. We find that the optimum fit has
. We give predictions for the charm
components of
the proton structure functions F2 and FL as functions of
x and Q2 and, in particular,
find that F2c is in good agreement with the existing
measurements.
We examine the Q2 range of validity of the
photon-gluon fusion model for electroproduction.
We emphasize the value of a precision measurement of the charm
component F2c at HERA.
Copyright Springer-Verlag
