The structure of Charm Jets in DIS

Reference A. Perieanu, presented at DIS 2005, Spring 2005
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Figures  (9a)  (9b)  (9c)  (9d)  (9e)  (9f)  (10a)  (10b)  (11a)  (11b)  (12a)  (12b)
Contact A. Perieanu, J. Bracinik, G. Grindhammer
Abstract The structure of charm jets in deep-inelastic scattering is studied with the H1 detector at HERA using an integrated luminosity of 50 pb-1. The event samples are in the phase space region 2 < Q^2 < 100 GeV^2 and 0.05 < y < 0.7. The charm events are tagged by a D*-meson required to have a transverse momentum p_t,D* > 1.5 GeV and pseudorapidity |eta_D*| < 1.5. Furthermore, the events are required to have at least one jet containing the D*-meson (DstarJet). If there is a second jet (OtherJet) in the event, it must have, like the DstarJet, p_t,jet > 1.5 GeV and |eta_jet| < 1.5. The structure of the DstarJet and the OtherJet is investigated by measuring the well-known jet shapes and subjet multiplicities as well as the angular distribution of a specific subjet of the DstarJet and the OtherJet with respect to its respective charm jet, defined to give a correlation with a corresponding gluon at the parton level. The latter distribution as well as the derived one of a characteristic angle alpha_0 x E_jet as a function of E_jet is motivated by the suppression of soft gluon radiation from heavy quarks, as expected from QCD ("dead cone effect"). In all distributions differences between the DstarJet and the OtherJet are observed. In general the data are found to be reasonably well described by the QCD model for charm production as implemented in RAPGAP 2.8 and JETSET 7.4.
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