High transverse momentum pi(o)-mesons have been measured with the H1 detect
or at HERA in deep-inelastic ep scattering events at low Bjorken-x, down to
x approximate to 4 . 10(-5). The measurement is performed in a region of s
mall angles with respect to the proton remnant in the laboratory frame of r
eference, namely the forward region. and corresponds to central rapidity in
the centre of mass system of the virtual photon and proton. This region is
expected to be particularly sensitive to QCD effects in hadronic final sta
tes. Differential cross-sections for inclusive pi(o)-meson production are p
resented as a function of Bjorken-x and the four-momentum transfer squared,
Q(2), and as a function of transverse momentum and pseudorapidity. A recen
t numerical BFKL calculation and predictions from QCD models based on DGLAP
parton evolution are compared with the data. (C) 1999 Elsevier Science B.V
. All rights reserved.