A bubble chamber investigation of π−+p elastic scattering at 1 200 MeV (K.E.) is reported. The total and differential cross-sections are determined. By extrapolation of the angular distribution, the 0° cross-section is derived and compared with the results obtained with the help of the dispersion relations and the optical theorem. The forward peak is investigated in terms of diffraction scattering and a value for the optical radius is derived.
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Using the CUSB-II detector at the Cornell Electron Storage Ring, we have measured Bμμ, the branching fraction into muons, of the Υ’’ meson. We find Bμμ(Υ’’)=(1.53±0.33±0.21)%, from which the Υ’’ total decay width is 25.5±5.0 keV. From this result we obtain αs=0.170−0.012+0.015, ΛMS¯=148−39+56 MeV. (MS¯ denotes the modified minimal-subtraction scheme).
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Using the CUSB-II detector at CESR we have measured the B ∗ cross section in the energy range from s = 10.61–10.65 GeV and 10.70 GeV to be 0.16±0.03 nb and 0.33±0.13 nb respectively. The photon energy for B ∗ →Bγ decays is measured to be 45.4±0.8 MeV, in agreement with our earlier determination. The implication of this measurement for future B factories is discussed.
Errors include systematic uncertainties.
We report on inclusive K 0 production in the region of the upsilon resonances (9.4–10.6 GeV). The K 0 yield for the resonances and continuum below the B B threshold is found to be constant at 0.82 ± 0.10 K 0 per observed hadronic event. At the ϒ (4S), however, the K 0 yield is significantly higher, 1.58 ± 0.35. This increase in K 0 production and the differential cross section d σ /d p of kaons are consistent with B B decay of the ϒ (4S) resonance with the bottom quarks subsequently decaying primarily into charmed quarks.
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ACCEPTANCE CORRECTED INCLUSIVE K0 MOMENTUM DISTRIBUTION AT THE UPSI(10570)0.
We have studied the topologies of hadronic events in e + e - annihilation data taken in the region of the upsilon resonances with the non-magnetic CUSB detectors at CESR. Using a thrust-like variable we compare the decay of ϒ, ϒ′ and ϒPrime; find for ϒ″ a significant excess of high thrust events, which we interpret as evidence for electric dipole transitions.
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The masses, total widths, and leptonic widths of three triplet s-wave bb¯ states ϒ(4S), ϒ(5S), and ϒ(6S) are determined from measurements of the e+e− annihilation cross section into hadrons for 10.55
VISIBLE CROSS SECTION INTO HADRONS.
The CUSB detector at the Cornell Electron Storage Ring has been used to measure R=σ(e+e−→hadrons)σ(e+e−→μ+μ−) in the c.m. energy regions between the ϒ′′ and the ϒ′′′, and above the ϒ′′′ up to s=11.6 GeV, with integrated luminosities of 5000 and 2100 nb−1, respectively. No narrow resonances are observed, and limits on the leptonic widths are presented. The average value of R increases by 0.31±0.06 across the flavor threshold.
UNCORRECTED VALUES OF R.
UNCORRECTED R VALUES BELOW AND ABOVE UPSI(10.5).
FULLY CORRECTED R VALUES, ASSUMING B AB PRODUCTION IS TOTALLY RESPONSIBLE FOR THE EXCESS ABOVE UPSI(10.5).
During an energy scan at the Cornell Electron Storage Ring, with use of the Columbia University-Stony Brook NaI detector, an enhancement in σ(e+e−→hadrons) is observed at center-of-mass energy ∼10.55 GeV. The mass and leptonic width of this state (ϒ′′′) suggest that it is the 4S13 bound state of the b quark and its antiquark. After applying to the data a cut in a (pseudo) thrust variable, the natural width is measured to be Γ=12.6±6.0 MeV, indicating that the ϒ′′′ is above the threshold for BB¯ production.
VISIBLE TOTAL HADRONIC CROSS SECTION FOR FIRST, THIRD AND FOURTH UPSILONS.
The ϒ, ϒ′, and ϒ′′ states have been observed at the Cornell Electron Storage Ring as narrow peaks in σ(e+e−→hadrons) versus beam energy. Data were collected during a run with integrated luminosity of 1000 nb−1, using the Columbia University-Stony Brook segmented NaI detector. The measured mass differences are M(ϒ′)−M(ϒ)=559±1(±3) MeV and M(ϒ′′)−M(ϒ)=889±1(±5) MeV, where the errors in parentheses represent systematic uncertainties. Preliminary values for the leptonic width ratios were also obtained.
HADRONIC EVENTS/SMALL-ANGLE BHABHA YIELD.
We have measured the cross section for p+p→p+X for MX2 up to a constant fraction of s. We observe no rise for 130
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