Charged particles and neutral kaons in photoproduced jets at HERA

Collaboration
Nov, 1997
36 pages
Published in:
  • Eur.Phys.J.C 2 (1998) 77-93
e-Print:
Report number:
  • DESY-97-229
Experiments:

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Abstract:
Charged particles (h±h^\pm) and \kz mesons have been studied in photoproduced events containing at least one jet of ET>8E_T > 8 GeV in a pseudorapidity interval (--0.5, 0.5) in the ZEUS laboratory frame. Distributions are presented in terms of transverse momentum, pseudorapidity and distance of the particle from the axis of a jet. The properties of \hpm within the jet are described well using the standard settings of PYTHIA, but the use of the multiparton interaction option improves the description outside the jets. A reasonable overall description of the \kz behaviour is possible with PYTHIA using a reduced value of the strangeness suppression parameter. The numbers of h±h^\pm and \kz within a jet as defined above are measured to be 3.25±0.02±0.283.25\pm0.02\pm0.28 and 0.431±0.013±0.0880.431\pm0.013\pm0.088 respectively. Fragmentation functions are presented for h±h^\pm and \kz in photoproduced jets; agreement is found with calculations of Binnewies et al. and, at higher momenta, with ppˉp\bar p scattering and with standard PYTHIA. Fragmentation functions in direct photoproduced events are extracted, and at higher momenta give good agreement with data from related processes in e+ee^+e^- annihilation and deep inelastic epep scattering.
Note:
  • 33 pages including 19 figures Report-no: DESY-97-229
  • positron p: colliding beams
  • exchange: one-photon
  • jet: photoproduction
  • K0: associated production
  • charged particle: associated production
  • fragmentation function
  • K0(S): hadronic decay
  • mass spectrum: (pi+ pi-)
  • transverse momentum: spectrum
  • rapidity spectrum