CERN Accelerating science

Preprint
Report number	CERN-OPEN-99-343
Title	Study of prompt $J/\psi$ production in hadronic Z decays
Preprint title	Study of prompt charmonium production in hadronic Z decay
Author(s)	Rousseau, D (CERN)
Publication	1997
Collaboration	ALEPH Collaboration
Imprint	19 Aug 1997
Number of pages	15
Presented at	International Europhysics Conference on High-Energy Physics, Jerusalem, Israel, 19 - 25 Aug 1997
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LEP ; ALEPH
Abstract	A measurement of prompt J/psi production with low model dependence is performed on 3.9 million hadronic Z decays collected by the ALEPH detector. The sample of J/psi at short decay-length shows an excess 46+/-12 prompt J/psi on a background of 57 B decay and 18 combinatorial events, yielding the branching ratio Br(Z->prompt J/psi X)= (3.00+/- 0.78(stat) +/- 0.30(syst) +/- 0.15(theo)) *10^-4. This result is consistent with a theoretical prediction allowing for color-octet gluon->J/psi as well as c quark fragmentation.
Submitted by	catherine.cart@cern.ch