2021 Impact factor 4.991
Particles and Fields
Eur. Phys. J. C 2, 287-300

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

We present a formulation which allows heavy quark $(c, b,
\ldots)$ 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 $c\overline{c}$ and $b\overline{b}$ 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 $\alpha_S(M_Z^2) = 0.118$. 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 $c\overline{c}$ electroproduction. We emphasize the value of a precision measurement of the charm component F2c at HERA.

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