We have examined charged multiplicities arising from p − p and p− p ̄ collisions over the range of center of mass energies, s , from 30 GeV to 1800 GeV. Results from Tevatron experiment E735 support the presence of double parton interactions. These processes can be seen to account for a large fraction of the increase in the non single diffraction inelastic cross section from energies of about 200 GeV to 1800 GeV.
Using the ARGUS detector at DORIS we have observed the prediction of the charged D ∗ meson in e + e − annihilation at a center of mass energy of 10 GeV. The D ∗ fragmentation function has been measured using the decay channels D ∗+ → D 0 π + and D 0 → K − π + and K − π + π + π − .
Production of the F meson by e + e − annihilation at high energies has been obsrved in the ϕπ final state with a mass of 1.975 ± 0.009 ± 0.010 GeV and a width consistent with the mass resolution. The yield of F production times branching ratio relative to μ pair production is R F ( x ⩾ 0.3) B (F ± → ϕπ ± ) = 0.061 ± 0.012 ± 0.018.
We present evidence for the production of Ξ· − , Ξ − in e + e − annihilation into hadrons. Our measurements yields: 0.026 ± 0.008 (stat.) ± 0.009 (syst.) Ξ − , Ξ − per hadronic event at W ∼ 34 GeV. Using our previous measurements of Λ, Λ and p, p production we obtain the relative yields (Ξ − , Ξ − /(Λ, Λ = 0.087 ± 0.03 ( stat. ) ± 0.03 ( syst. ) and (Ξ − , Ξ − /( p , p = 0.033 ± 0.011 ( stat. ) ± 0.011 ( syst. ) .
Data on inclusive kaon production in e+e− annihilations at energies in the vicinity of the ϒ(4S) resonance are presented. A clear excess of kaons is observed on the ϒ(4S) compared to the continuum. Under the assumption that the ϒ(4S) decays into BB¯, a total of 3.38±0.34±0.68 kaons per ϒ(4S) decay is found. In the context of the standard B-decay model this leads to a value for (b→c)(b→all) of 1.09±0.33±0.13.
Using the data sets of 17.3 pb$^{-1}$ collected at $\sqrt{s}=$ 3.773 GeV and 6.5 pb$^{-1}$ collected at $\sqrt{s}=$ 3.650 GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 18 exclusive light hadron final states produced in $e^+e^-$ annihilation at the two energy points.
By analyzing the data sets of 17.3 pb$^{-1}$ taken at $\sqrt{s}=3.773$ GeV and 6.5 pb$^{-1}$ taken at $\sqrt{s}=3.650$ GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 12 exclusive light hadron final states produced in $e^+e^-$ annihilation at the two energy points. We have also set the upper limits on the observed cross sections and the branching fractions for $\psi(3770)$ decay to these final states at 90% C.L.
The production of Jψ mesons in Z0 decays is studied using 3.6 million hadronic events recorded by the OPAL detector at LEP. The inclusive Z0 to Jψ and b-quark to Jψ branching ratios are measured from the total yield of Jψ mesons, identified from their decays into lepton pairs. The Jψ momentum distribution is used to study the fragmentation of b-quarks. The production rate of ψ′ mesons, identified from their decays into a Jψ and a π+π− pair, is measured as well. The following results are obtained: ${Br(Z^{0}⌝ghtarrow {⤪ J}/ i X)=(3.9pm 0.2pm 0.3)cdot 10^{-3} {⤪ and} ↦op Br(Z^0⌝ghtarrow i ^⌕ime X)=(1.6pm 0.3pm 0.2)cdot 10^{-3}, }$ where the first error is statistical and the second systematic. Finally the Jψ sample is used to reconstruct exclusive b-hadron decays and calculate the corresponding b-hadron branching ratios and masses.
The reaction γγ → 2 π + 2 π − π 0 has been studied using the the ARGUS detector at the e + e − storage ring DORIS II at DESY. The production of the vector-meson pair ωϱ 0 is observed for the first time. The cross section for γγ → ωϱ 0 and the topological cross section for γγ → 2 π + 2 π − π 0 are given. The angular distribution in ωϱ 0 events do not indicate any specific dominant spin-parity; they are consistent with isotropic production and decay of the ω and ϱ 0 mesons over the available W γγ range.
Using the ARGUS detector at the DORIS II e + e − storage ring we have measured direct photons from the decay ???(1 S )→ γgg . The ratio R γ = Γ (???(1S)→ γgg )/ Γ (???(1S)→ ggg )=(3.00±0.13±0.18)% has been determined, from which we deduce values of the strong coupling constant α s =0.225±0.011±0.019 and the QCD scale parameter Λ MS =115±17±28 MeV defined in the modified minimal-subtraction scheme. The shape of the measured spectrum clearly rules out the predictions of the lowest order QCD calculations.
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