P. Murat

Measurement of the decay

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY we have investigated the decays B 0 → D ∗− e + v and B 0 →D ∗− μ + ν. The B 0 mesons were produced in 39600 ϒ(4 S )→ B 0 B 0 decays. Assuming electron-muon universality we obtain a branching ratio BR ( B 0 → D ∗− e + v)= BR ( B 0 → D ∗− γm + ν)=(7.0±1.2±1.9)% .

A measurement of the tau mass

Using the ARGUS detector at the DORIS II storage ring, a new measurement of the mass of the τ lepton has been obtained. An analysis of the tau pseudomass spectrum for decays of the type τ− → π−π−π+ντ finds mτ = 1776.3±2.4±1.4 MeV/c2. This result also leads to an improvement of the upper limit on the ντ mass to mντ < 31 MeV/c2 at the 95% confidence level.

A partial wave analysis of the decay D0 → KS0π+π−

Abstract Using the ARGUS detector at the DORIS-II electron-positron storage ring at DESY, we have investigated the exclusive decay D ∗+ → D 0 π + , D 0 → K S 0 π + π − . From a partial wave analysis of the KS0π+π− system we find that (71.8± 4.2 ± 3.0)% are D 0 → K ∗− π + and (22.7 ± 3.2 ± 0.9)% are D 0 → K 0 ϱ 0 with a relative phase of (−137 ± 7 ± 3)° between the channels. The remaining fraction can be described by several channels involving excited resonances, but not by a three-body phase space decay, thus giving first evidence for D0 decays into K 0 ∗ (1430) − π + , K 0 f 0 (1975), K 0 f 2 (1270) , and K 0 f 0 (1400) .

Evidence for the production of the charmed, doubly strange baryon Ωc in e+e− annihilation

Abstract Using the detector ARGUS at the storage ring DORIS II of DESY, we have found evidence for the production of the charmed and doubly strange baryon Ω c through its decay channel Ξ − K − π + π + . Its mass has been determined to be ((2719.0±7.0±2.5)MeV/ c 2 , and the product of production cross section and branching ratio the above channel to be (2.41±0.90±0.30) pb.

Measurement of the decay B− → D∗0ℓ−λ

Abstract Using the ARGUS detector at the e + e − storage ring DORIS II at DESY we have studied the decay B − → D ∗0 l − λ , where l − = e − or μ − , using the D 0 γ and D 0 π 0 decay modes of the D ∗0 meson. B mesons were produced in 209 000 decays of γ (4S). Assuming electron-muon universality, we obtain a value for the branching ratio of BR ( B − → D ∗0 l − λ )= (5.8 ± 1.4 ± 1.3)% .

Measurement of inclusive baryon production inB meson decays

AbstractUsing the ARGUS detector at thee+e− storage ring DORIS II at DESY, we have studiedB meson decays into baryonsp and Λ. From the simultaneous analysis ofp and Λ yields,p

Search for neutrinoless

\bar p

decays

and Λ