F. H. Heimlich

Limits on axion and light Higgs boson production in ϒ (1S) decays

Abstract We have searched for axion and light Higgs boson production in the channel ϒ (1 S ) → (a 0 or h 0 ) + γ , where the non-interacting axion a 0 and the Higgs boson h 0 do not decay in the detector. We find no evidence for an axion and give an upper limit, Br( ϒ (1S) → a 0 γ ) −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

Search for exotic tau decays

Abstract The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes τ →e γ , τ →e π 0 , and τ →e η . No signal was observed. We obtained the following 90% CL upper limits on the branching fractions: B ( τ →e γ ) −4 , B ( τ →e π 0 ) −4 , B ( τ →e η ) −4 .

The Michel parameter for the decay τ→eνν

Abstract The Crystal Ball detector at the Doris II storage ring at DESY has been used to study the electron energy spectrum of the decay τ→evv. In the standard model the Lorentz structure of the decay matrix element is of the well known V-A type, resulting in a Michel parameter of p =0.75. Our spectrum is found to be consistent with this value. A fit yields the value of 0.64±0.07.

Observation of the exclusive decayB→evD* and search forB→evπ0

The Crystal Ball detector at thee+e− storage ring DORIS II has been used to analyze exclusive semileptonic decays ofB mesons produced at γ(4S) energies. The decayB→evD* has been observed with a branching ratio of (7.0±1.8±1.4)% using theπ°D decay mode of theD*. In addition we have searched for the exclusive semileptonic decayB±→e±vπ0. We find an upper limit onB±→e±vπ0 of 0.22% at the 90% CL.

InclusiveJ/ψ production in decays ofB mesons

The production ofJ/ψ inB meson decays has been measured on the Γ(4S) resonance using the Crystal Ball detector at thee+e− storage ring DORIS II. TheJ/ψ is identified by itse+e− decay mode. We obtain a branching ratio of BR(B→J/ψX)=(1.12±0.33±0.25)% in good agreement with theoretical predictions based on color suppression. TheJ/ψ momentum distribution is observed to be peaked at high values. This implies a substantial contribution from directB meson decays to theJ/ψ. In addition upper limits onJ/ψ production in Γ(1S) and Γ(2S) decays and in continuum processes are determined.

Measurement of the branching ratios for the decays τ→hadron π0ν and τ→hadron π0π0ν

Abstract The Crystal Ball detector at the DORIS II storage ring at DESY has been used to measure the branching ratios for the decay modes τ ± →h ± π 0 ν and τ ± →h ± π 0 π 0 ν , where h ± is any charged hadron. The results are BR( τ ± → h ± π 0 ν ) = (22.0±0.8±1.9)%, BR( τ ± → h ± π 0 π 0 ν ) = (5.7±0.5 +1.0 −1.7 )%. The first result is in good agreement with the present world average. The decay mode h ± π 0 π 0 ν is reconstructed in τ decays for the first time. Its branching ratio, however, is somewhat lower than the corresponding world average, and therefore tends to increase the one-prong problem.

Search for radiativeB meson decays

AbstractThe Crystal Ball detector at thee+e− storage ring DORIS-II has been used to search for radiativeB meson decays, especially of the typeb→sγ. No monoenergetic γ-lines have been found in the inclusive photon spectrum from У(4S) decays, and upper limits are obtained for radiative decays ofB mesons to various strange mesons and to theD*. Integrating the photon spectrum over the corresponding energy range, we find

Measurement of π0 and η meson production in e+e- annihilation at {Mathematical expression} near 10 GeV

BR(B \to \gamma X)< 2.8 \times 10^{ - 3} ,