The analyzing power,$A_{oono}$, and the polarization transfer observables$K_{onno}$,$K_{os''so}$
Position 'A' (see text for explanation).
Position 'A' (see text for explanation).
Position 'A' (see text for explanation).
We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The observables are obtained to high jet resolution scales with the JADE, Durham, Cambridge and cone jet finders, and compared with the predictions of various QCD and Monte Carlo models. The strong coupling strength, alpha_s, is determined at each energy by fits of O(alpha_s^2) calculations, as well as matched O(alpha_s^2) and NLLA predictions, to the data. Matching schemes are compared, and the dependence of the results on the choice of the renormalization scale is investigated. The combination of the results using matched predictions gives alpha_s(MZ)=0.1187+{0.0034}-{0.0019}. The strong coupling is also obtained, at lower precision, from O(alpha_s^2) fits of the c.m.s. energy evolution of some of the observables. A qualitative comparison is made between the data and a recent MLLA prediction for mean jet multiplicities.
Overall result for ALPHAS at the Z0 mass from the combination of the ln R-matching results from the observables evolved using a three-loop running expression. The errors shown are total errors and contain all the statistics and systematics.
Weighted mean for ALPHAS at the Z0 mass determined from the energy evolutions of the mean values of the 2-jet cross sections obtained with the JADE and DURHAMschemes and the 3-jet fraction for the JADE, DURHAM and CAMBRIDGE schemes evaluted at a fixed YCUT.. The errors shown are total errors and contain all the statistics and systematics.
Combined results for ALPHA_S from fits of matched predicitions. The first systematic (DSYS) error is the experimental systematic, the second DSYS error isthe hadronization systematic and the third is the QCD scale error. The values of ALPHAS evolved to the Z0 mass using a three-loop evolution are also given.
The elastic proton-helium differential cross sections have been determined for 5 different incident laboratory energies from 40 to 400 GeV in the range 0.003 < l t I < 0.52 (GeV/c)2. The differential cross section drops 4 - 5 orders of magnitude to the first dip at I t I = 0.22 (GeV/c)2. A Glauber analysis is performed on the data. The inelastic intermediate states are found to be important. The shrinkage of the slope of the differential cross section is measured. The rate of shrinkage is twice as large as in the p-p case. Results on the real part of the elastic scattering amplitude at forward angle and at the dip structure ( l t l similar/equal to 0.22) are presented.
No description provided.
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AVERAGED DATA FOR 44.9 AND 45.5 GEV.
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Proton-proton and proton-deuteron elastic scattering has been measured for incident laboratory energy from 50 to 400 GeV; minimum |t| values were, for p−p, 0.0005 (GeV/c)2, and for p−d, 0.0008 (GeV/c)2. From the differential cross sections we have determined the ratios of the real to imaginary parts of the forward scattering amplitude, ρpp and ρpd, for p−p and p−d scattering. Using a Glauber approach and a sum-of-exponentials form factor we obtain ρpn for p−n scattering.
No description provided.
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FROM GLAUBER ANALYSIS. THE SYSTEMATIC ERRORS DUE TO THE UNCERTAINTY IN THE DEUTERON FORM FACTOR ARE COMPARABLE WITH THE STATISTICAL ERRORS.
Inclusive coherent proton diffraction dissociation on helium has been measured in the four-momentum transfer and missing-mass region 0.04<|t|<0.40 (GeV/c)2, MX2<10 GeV2 and for incident proton beam momenta from 46 to 400 GeV/c. We find that the differential cross section d2σdtdMX2 varies slowly with energy, reveals a pronounced peak at MX2≃2 GeV2, and at large masses behaves approximately as 1MX2. The cross section falls exponentially as |t| increases, with a large slope parameter at small momentum transfers and a substantially smaller one at large |t| values, with no clear dip between the two regions as seen in elastic scattering. We compare the experimental t distributions to Glauber-model predictions and find the data provide a sensitive test of the assumptions on the details of the elementary proton diffraction-dissociation amplitudes and on the total cross sections of the diffractively produced states.
No description provided.
No description provided.
AVERAGED DATA FOR 200 AND 259 GEV.
We report results from a measurement of the inclusive processes pp→Xp and pd→Xd in the range 5
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Measurements of target asymmetries and double-polarization observables for the reaction $\gamma p\to p\pi^0\pi^0$ are reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility (Bonn University) using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided transversely polarized protons. Linearly polarized photons were produced via bremsstrahlung off a diamond crystal. The data cover the photon energy range from $E_{\gamma}$=650 MeV to $E_{\gamma}$=2600 MeV and nearly the complete angular range. The results have been included in the BnGa partial wave analysis. Experimental results and the fit agree very well. Observed systematic differences in the branching ratios for decays of $N^*$ and $\Delta^*$ resonances are attributed to the internal structure of these excited nucleon states. Resonances which can be assigned to SU(6)$\times$O(3) two-oscillator configurations show larger branching ratios to intermediate states with non-zero intrinsic orbital angular momenta than resonances assigned to one-oscillator configurations.
Target asymmetry for $\pi^0\pi^0$ as a function of the polar angle for bins of the incident photon energy in the range of $E_\gamma$ = 650-2600 MeV.
Target asymmetry for $\pi^0\pi^0$ as a function of the $\pi^0\pi^0$ invariant mass for bins of the incident photon energy in the range of $E_\gamma$ = 650-2600 MeV.
Target asymmetry for $\pi^0\pi^0$ as a function of the $\phi^*$ angle for bins of the incident photon energy in the range of $E_\gamma$ = 650-2600 MeV.
The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlatio
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
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