arXiv subjects

ARGUS Collaboration

Publications and source records attributed to ARGUS Collaboration.

2 recordsLinked to original sources

arXiv2000

A Search for the Electric Dipole Moment of the Tau-Lepton

Using the ARGUS detector at the e+e- storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor d_tau of the tau lepton in the production of tau pairs at q^2=100 GeV^2. This is the first direct measurement of this CP violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed tau decay products. No evidence for CP violation was found, and we derive the following results: Re(d_tau)=(1.6+-.9)*10^(-16) ecm and Im(d_tau)=(-0.2+-0.8)*10^(-16) ecm, where statistical and systematic errors have been combined.

hep-ex↗

arXiv1997

Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

Using the ARGUS detector at the $e^+ e^-$ storage ring DORIS II, we have measured the Michel parameters $ρ$, $ξ$, and $ξδ$ for $τ^{\pm}\to l^{\pm} ν\barν$ decays in $τ$-pair events produced at center of mass energies in the region of the $Υ$ resonances. Using $τ^\mp \to ρ^\mp ν$ as spin analyzing tags, we find $ρ_{e}=0.68\pm 0.04 \pm 0.08$, $ξ_{e}= 1.12 \pm 0.20 \pm 0.09$, $ξδ_{e}= 0.57 \pm 0.14 \pm 0.07$, $ρ_μ= 0.69 \pm 0.06 \pm 0.08$, $ξ_μ= 1.25 \pm 0.27 \pm 0.14$ and $ξδ_μ= 0.72 \pm 0.18 \pm 0.10$. In addition, we report the combined ARGUS results on $ρ$, $ξ$, and $ξδ$ using this work und previous measurements.

hep-ex↗