A measurement of the semileptonic branching ratio ${\rm BR}({b-baryon} \rightarrow {\rm p} l \bar{\nu} X)$ and a study of inclusive $\pi^{\pm}$, $\rm{K}^{\pm}$, ($\rm{p,\bar{p}}$) production in Z decays

The ALEPH Collaboration:     R. Barate - et al.

doi:doi:10.1007/s100529800975

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2023 Impact factor 4.2

Particles and Fields

Eur. Phys. J. C 5, 205-227
DOI 10.1007/s100529800975

A measurement of the semileptonic branching ratio ${\rm BR}({\mbox{b-baryon}} \rightarrow {\rm p} l \bar{\nu} X)$ and a study of inclusive $\pi^{\pm}$ , $\rm{K}^{\pm}$ , ( $\rm{p,\bar{p}}$ ) production in Z decays

The ALEPH Collaboration
R. Barate - et al.

Laboratoire de Physique des Particules (LAPP), IN²P³-CNRS, F-74019 Annecy-le-Vieux Cedex, France

Received 1 December 1997 / Published online: 4 August 1998

Abstract
Inclusive $\pi^{\pm}$ , $\rm{K}^{\pm}$ and ( $\rm{p,\bar{p}}$ ) production is investigated using data recorded by the ALEPH detector between 1992 and 1994. The momentum spectra and multiplicities are measured separately in $\rm{Z}\rightarrow \rm{b\bar{b}}$ , $\rm{Z}\rightarrow \rm{c\bar{c}}$ and $\rm{Z}\rightarrow \rm{u\bar{u},d\bar{d},s\bar{s}}$ decays. The number of protons found in b-hadron decays is used to estimate the fraction of b-baryons in b events to be $(10.2\pm 0.7\pm 2.7)\%$ assuming BR(b-baryon $\rightarrow \rm{p}X)=(58\pm 6)\%$ . From an additional study of proton-lepton correlations in b events, the branching ratio ${\rm BR}({\mbox{b-baryon}}\rightarrow {\rm p} l\bar{\nu}X) =(4.63\pm 0.72 \pm 0.98)\%$ is obtained. The ratio ${\rm BR}({\mbox{b-baryon}} \rightarrow {\rm p} l \bar{\nu} X)/ {\mbox{BR(b-baryon}}\rightarrow {\rm p} X)$ is found to be $0.080\pm 0.012 \pm 0.014$ .