The partial decay width R-c of the Z into c (c) over bar quark pair and the number of charm quarks n(c) per b decay are measured with the DELPHI detector at LEP 1. Particle identification provides clear DO, D+, D-s(+) and Lambda(c)(+) signatures. The charm hadron production rate is measured in each channel by a fit to the scaled energy, impact parameter information and the invariant mass spectrum. Two measurements of R-c are presented, from the D*(+) production rate and from the overall charm counting, including strange charm baryon production, in c (c) over bar events. The multiplicity n(c), which includes hidden c (c) over bar and strange charm baryon production, is inferred from the charm counting in bb events. The final results are R-c = 0.1665 +/- 0.0095 and n(c) = 1.166 +/- 0.086.
Measurements of the Z partial decay width into c(c)over-bar and multiplicity of charm quarks per b decay
DE ANGELIS, Alessandro;DE LOTTO, Barbara;SCURI, Fabrizio;
2000-01-01
Abstract
The partial decay width R-c of the Z into c (c) over bar quark pair and the number of charm quarks n(c) per b decay are measured with the DELPHI detector at LEP 1. Particle identification provides clear DO, D+, D-s(+) and Lambda(c)(+) signatures. The charm hadron production rate is measured in each channel by a fit to the scaled energy, impact parameter information and the invariant mass spectrum. Two measurements of R-c are presented, from the D*(+) production rate and from the overall charm counting, including strange charm baryon production, in c (c) over bar events. The multiplicity n(c), which includes hidden c (c) over bar and strange charm baryon production, is inferred from the charm counting in bb events. The final results are R-c = 0.1665 +/- 0.0095 and n(c) = 1.166 +/- 0.086.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.