Speaker
Shuangshi Fang
(DESY)
Description
The charm fragmentation function has been measured in D* photoproduction with
the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The
fragmentation function is measured versus z, the ratio of E+p_parallel for the
D* meson and that for the associated jet, where E is the energy and p_parallel
the longitudinal momentum relative to the jet axis. Jets were reconstructed
using the k_T clustering algorithm and required to have transverse energy
greater than 9 GeV. The D* meson associated with the jet was required to have
a transverse momentum greater than 2 GeV. The measured function is compared to
different fragmentation models incorporated in leading-logarithm Monte Carlo
simulations and a next-to-leading-order calculation. The results are similar
to those from e+e- experiments.
The process of charm quark fragmentation is studied using $D^{*\pm}$ meson
production in deep-inelastic scattering as measured by the H1 detector at
HERA. Two different regions of phase space are investigated defined by the
presence or absence of a jet containing the $D^{*\pm}$ meson in the event.
The parameters of fragmentation functions are extracted for QCD models
based on leading order matrix elements and DGLAP or CCFM evolution of
partons together with string fragmentation and particle decays.
Additionally, they are determined for a next-to-leading order QCD
calculation in the fixed flavour number scheme using the independent
fragmentation of charm quarks to $D^{*\pm}$ mesons.
Primary authors
Monica Turcato ZEUS Collaboration
(Hamburg University)
Shuangshi Fang
(DESY)
