A study of three-prong tau decays with charged kaons

The OPAL Collaboration:     G.Abbiendi - et al.

doi:doi:10.1007/s100520000272

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2023 Impact factor 4.2

Particles and Fields

Eur. Phys. J. C 13, 197-212
DOI 10.1007/s100520000272

A study of three-prong tau decays with charged kaons

The OPAL Collaboration

G.Abbiendi $^{\rm 2}$ - et al.

²Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy

Received: 9 July 1999 / Published online: 17 February 2000 - © Springer-Verlag 2000

Abstract
From an analysis of the ionisation energy loss of charged particles selected from a sample of 147926 ${\rm e}^+{\rm e}^- \!\!\rightarrow\! \tau^+\tau^-$ candidates recorded in the OPAL detector at ${\rm e}^+{\rm e}^-$ centre-of-mass energies near the ${\rm Z}^0$ resonance, we determine the branching ratios:

$\begin{eqnarray*}{\rm Br}(\tau^-\rightarrow \,\nu_\tau\, {\rm K}^-\pi^-\pi^+ (\p... ...{\rm K}^+ (\pi^0)) & = & 0.159\pm0.053\pm0.020 \;\% , \nonumber \end{eqnarray*}$

where the $(\pi^0)$ notation refers to decay modes with or without an accompanying $\pi^0$ . The

$\begin{displaymath}\tau^- \rightarrow \nu_\tau {\rm K}^-\pi^- \pi^+ (\pi^0)\end{displaymath}$

final states occurring through $\tau^- \rightarrow \nu_\tau {\rm K}^-{\rm K}^0_{\rm S} (\pi^0)$ are treated as background in this analysis.
We also examine the resonant structure of $\tau^- \!\!\rightarrow\!\! \,\nu_\tau\, {\rm K}^-\pi^-\pi^+$ candidates. Under the assumption that the resonant structure is dominated by the K₁ resonances, we determine:

$\begin{eqnarray*}R & = & {{{\rm Br}(\tau^-\rightarrow \,\nu_\tau\, {\rm K}_1(127... ...\tau\, {\rm K}_1(1270))} } = 0.71 \pm 0.16 \pm 0.11 . \nonumber \end{eqnarray*}$