[en] We report the results of a study of the production mechanism of inclusive dimuon production from the reaction p + p → μ μ + X at CERN-ISR. The present experiment was done at the center of mass energies √s + 62 and 44 GeV and in the dimuon pair invariant mass region m = 3 to 25 GeV. The dependence on the Feynman variable x has been measured. The average transverse momentum is found to increase with √s and with mass and reaches < p_T> = 1.9 GeV and is compatible with predictions from QCD gluon processes

[en] Preliminary results from the Crystal Ball experiment at DORIS II are presented on the radiative transitions from the UPSILON(2S) resonance. Three photon lines are observed in the inclusive photon spectrum of UPSILON(2S) resonance decays, at energies of 108.2 +- 0.7, 127.1 +- 0.8 and 160.0 +- 2.4 MeV, with an estimated systematic error of +- 4 MeV. The branching ratios are measured to be (6.0 +- 0.7)%, (6.6 +- 0,8)% and (2.6 +- 0.7)% respectively. The two lower energy photon lines are also observed in the exclusive channel UPSILON(2S)→γγl l^-, consistent with the hypothesis that they correspond to the radiative transitions from UPSILON(2S) to the 3P/sub 2,1,0/ states of bb-bar

[en] The reaction γγ→π⁰eta has been investigated with the Crystal Ball detector at the DESY storage ring DORIS II. Formation of delta(980) and A₂(1320) has been observed with γγ partial widths GAMMA/sub γγ/(A₂) = 1.14 +- 0.20 +- 0.2 6 keV and GAMMA/sub γγ/(delta)B(delta→πeta) = 0.19 +- 0.07 /sub -0.07//sup +0.10/ keV

[en] The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reaction e⁺e^-→e⁺e^-γ*γ*→e⁺e^-γγ, where X is a narrow resonance with mass between 100 and 3000 MeV. Formation of π⁰, eta, and eta' mesons is observed, and the following meson partial widths are obtained: Γ/sub π/₀/sub Γ/₀/sub →//sub γ//sub γ/ = 7.7 +- 0.5 +- 0.5 eV, Γ/sub eta//sub -//sub γ//sub γ/ = 0.514 +- 0.017 +- 0.035 keV, and Γ/sub eta//sub '//sub →//sub γ//sub γ/ = 4.7 +- 0.5 +- 0.5 keV. No other narrow resonances are observed, and upper limits are given for the product Γ/sub X//sub →//sub γ//sub γ/B/sub X//sub →//sub γ//sub γ/. .AE

[en] We have searched for axion and light Higgs boson production in the channel Υ(1S)→(a⁰ or h⁰)+γ, where the non-interacting axion a⁰ and the Higgs boson h⁰ do not decay in the detector. We find no evidence for an axion and give an upper limit, Br(Υ(1S)→a⁰γ)<4.0x10^-5 (90% CL), for long-lived axions. Combining our limit with the previous search in J/ψ decays, we are able to rule out the axion in the standard model with first order QCD corrections. Our Υ(1S) data also rule out a Higgs boson with mass m_h<86 MeV. (orig.)

[en] The Crystal Ball detector at the DESY storage ring DORIS II has been used to study radiative decays of the Υ(2S) resonance. We report on the analysis of the exclusive channel Υ(2S)→γchi/sub b/, chi/sub b/→γΥ(1S)→e⁺e^- or μ⁺μ^-. We detect two chi/sub b/ states by observing two monochromatic photon lines at energies (107.0 +- 1.1 +- 1.3) MeV and (131.7 +- 0.9 +- 1.3) MeV, respectively. The product branching ratios B[Υ(2S)→γchi/sub b/] x B[chi/sub b/→γΥ(1S) ] are (1.6 +- 0.3 +- 0.2)% for the first state and (2.1 +- 0.3 +- 0.3)% for the second. For the product branching ratio of the third chi/sub b/ state, which has been observed in inclusive measurements, we find an upper limit of 0.2% (90% C.L.). Combining our results with inclusive measurements, branching ratios for chi/sub b/→γΥ(1S) are derived. Using theoretical estimates for the radiative widths of the chi/sub b/ states, we determine their hadronic widths; the results are compared with QCD predictions

[en] We have investigated the hadronic transitions UPSILON(2S) → π⁰π⁰UPSILON(1S) → γγγγl +l^- (l = μ or e) and UPSILON(2S) → π⁺π^-UPSILON(1S) → π⁺π ^-e⁺e^- using the Crystal Ball detector at the DESY e⁺e^- storage ring DORIS II. Using the present world-average value of B/sub l/l(UPSILON(1S)) = 2.9 +- 0.3)% we derive branching ratios B(UPSILON(2S) → π⁰π⁰UPSILON(1S)) = (8.0 +- 1.5)% and B(UPSILON(2S) → π⁺π^-UPSILON(1S)) = (16.9 +- 4.0)%. We also present results on the invariant-mass spectra and the angular distributions of the dipion system

[en] We have searched for axion and light Higgs boson production in the channel Υ(1S)→{a⁰ or h⁰}+γ, where the non-interacting axion a⁰ and the Higgs boson h⁰ do not decay in the detector. We find no evidence for an axion and give an upper limit, Br(Υ(1S)→a⁰γ)<4.0x10^-5 (90% C.L.) for long-lived axions. Combining our limit with the previous axion search in J/ψ decays, we are able to rule out the standard light axion. Our Υ(1S) data also rule out a Higgs boson with mass m_h<86 MeV. (orig.)

[en] Results from an experiment studying pp → μ⁺μ^-X at the ISR with the highest possible energy of √s = 62 GeV are presented. With relatively high statistics at these energies, the measurements extend to very high muon-pair masses. Associated hadron multiplicities are observed. The continuum of the pair spectra exhibits scalling. The data allow the extraction of the explicit dependence on xsub(Feyn), the transverse momentum Psub(T), and the decay angle THETA. The angular distribution is flat at the T, and 1 + cos² THETA otherwise. J and UPSILON are seen and measured, as well as very high mass events. Limits of resonance production are estimated. (orig.)

[en] The reaction e⁺e^-→e⁺e^-etaπ⁰π⁰ has been observed with the Crystal Ball detector at the DORIS II storage ring at DESY. The etaπ⁰π⁰ mass spectrum is dominated by the eta', and the two-photon width Γ/sub eta//sub '//sub →//sub γ//sub γ/ is determined to be 4.6 +- 0.4 +- 0.6 keV. Limits on Γ/sub X//sub →//sub γ//sub γ/ x B/sub X//sub →//sub eta//sub π//sub π/ are given for other possible states