Speaker
Dr
Eli Ben-Haim
(LPNHE Paris)
Description
The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP in the year 1994. The average value of xb^weak= Eb^weak/E_beam is measured to be 0.699 +/- 0.011. The resulting xb^weak distribution is then analyzed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract the non-perturbative component to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: a= 1.84^+0.23_-0.21 and b=0.642^+0.073_-0.063 with a correlation factor rho =92.2%. Combining the present measurement of b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of xb^weak is found to be 0.7092 +/- 0.0025 and the non-perturbative fragmentation component is also extracted. Using the combined distribution, a better determination of the Lund parameters is then obtained: a= 1.48^+0.11_-0.10 and b=0.509^+0.024_-0.023 with a correlation factor rho = 92.6%.
Authors
DELPHI Collaboration
(CERN)
Dr
Eli Ben-Haim
(LPNHE Paris)
