The impact of the ARGUS experiment to elementary particle physics is reviewed. More than ten years of data taking has allowed ARGUS to contribute significantly to our understanding of beauty and charmed hadrons, τ Leptons, ϒ mesons, ϒϒ interactions and fragmentation processes. In particular the ARGUS measurements of CKM matrix elements opened up a new window on the Standard Model.

We report on a high statistics study of π0 and η production in continuum events and in direct decays of the Γ(1S) and Γ(2S) resonances. The measured production rates per event are\(\left\langle {n_{\pi ^0 } } \right\rangle\)=3.22 ± 0.07 ± 0.31 (3.97 ± 0.23 ± 0.38) and 〈n η〉=0.19 ± 0.04 ± 0.04 (0.40 ± 0.14 ± 0.09) for continuum events (direct Γ(1S) decays).

We report on a high statistics study of π0 and η production in continuum events and in direct decays of the Γ(1S) and Γ(2S) resonances. The measured production rates per event are $$\left\langle {n_{\pi ^0 } } \right\rangle$$ =3.22 0.07 0.31 (3.97 0.23 0.38) and 〈n η〉=0.19 0.04 0.04 (0.40 0.14 0.09) for continuum events (direct Γ(1S) decays).

The correlations betweenp \(\bar p\),\(\Lambda \bar \Lambda \),\(\Xi ^ - \bar \Lambda \) and\(\Lambda (1520)\bar \Lambda \) baryons have been measured ine + e − continuum events and in direct Ψ decays. The observed correlations exclude the production of point-like diquark-antidiquark pairs as the dominant source of baryons. Information concerning angular momentum compensation follows from the observed\(\Lambda (1520)\bar \Lambda \) correlation.

Using the ARGUS detector at the electron-positron storage ring DORIS II at DESY, we have measured the branching ratios of theD0 meson decays into\(\overline {K^0 } \omega \),\(\overline {K^0 } \eta \) and\(\overline {K^{*0} } \eta \) relative to theK−π+ mode. Using the known branching ratio Br(D0→Kπ+)=(4.2±0.4±0.4)% we find\(Br(D^0 \to \overline {K^0 } \omega ) = (4.2 \pm 1.6 \pm 0.9)\% ,Br(D^0 \to \overline {K^0 } \eta )< 2.7\% \) (90% CL) and\(Br(D^0 \to \overline {K^{*0} } \eta )< 2.9\% \) (90% CL).

Using the ARGUS detector at the e+e− storage ring DORIS II, we have measured the average polarization of D∗+ mesons originating from exclusive decays B̄0 → D∗+ℓ−ν. By comparing the D∗+ decay angular distribution to a functional form 1 + α cos2≡, we determine α to be α=0.7±0.9. This value of α leads to a ratio of longitudinal to transverse decay with Γl/ΓT=0.85±0.45, which allows the determination, |Vcb|=0.052±0.011. The importance of the transverse helicity component is manifested in the q2 and lepton spectra,which are also presented.

Using the ARGUS detector at thee+e− storage ring DORIS II, we have investigated inclusive production of π±,K±,K s 0 and\(\bar p\) in multihadron events at 9.98 GeV and in direct decays of the ϒ(1S) meson, i.e. from quark and gluon fragmentation. The most pronounced difference is the rate of baryon production. The Lund Monte Carlo program gives a reasonable qualitative description, although it cannot reproduce our data in detail.

We report on a high precision measurement of ϕ-meson production in continuum events and in direct decays of the Υ(1S)- and Υ(2S)-mesons. The ratio of the total production rate of ϕ-mesons in direct Υ(1S)- and Υ(2S)-decays over that in continuum events is 1.32±0.08±0.09 and 1.07±0.13±0.11 respectively. This is compatible with the corresponding ratio obtained for lighter mesons, but is appreciably smaller than the relative baryon production rate.

We report on the first observation of Δ(1232)++ and Δ(1232)++¯ baryons in e+e− annihilation at energies around 10 GeV, using the ARGUS detector at DORIS II. The sum of the rates of Δ++ and Δ++¯ per hadronic event in the continuum is measured to be 0.040±0.008±0.006, and the rate in direct ϒ(1S) decays is 0.124±0.016±0.015. The momentum spectrum of Δ++ baryons in direct ϒ(1S) decays has been measured.

The detector ARGUS has been designed as a universal tool to investigate final states from e+e− annihilation processes in the energy range of the ϒ resonances. ARGUS started operation in October 1982 and has since successfully taken data at the ϒ(1S), ϒ(2S) and ϒ(4S) energies, and in the nearby continuum. The detector combines excellent charged particle identification and good photon energy resolution over more than 90% of the full solid angle. A particle originating from the interaction vertex and leaving the beam tube traverses the following components: the vertex drift chamber, the main drift chamber which determines its momentum and specific ionization, the time-of-flight system through which its velocity is determined, and the electromagnetic calorimeter. Muons pass through the magnet coils and the flux return yoke and finally hit the muon chamber system which surrounds the detector. The momentum resolution of ARGUS is σ(pT)PT = (0.012 + (0.009pT[GeV/c])2)12, the photon energy resolution in the barrel shower counters is σ(E)E = (0.0722+0.0652E[GeV])12. Combining the information from all p devices, more than 80% of all charged hadrons can be recognized unambiguously. The electron-hadron and muon-hadron rejection rates are 1:200 and 1:50 respectively.