Using a 320 GeV c π − beam incident on three different target materials Al, Fe, and U, the A -dependence of charm production is studied by measuring the yield of prompt single muons. Parametrizing the charm cross section as σ cc ( π − A) = σ 0 Aα the measured α values are α ( μ + ) = 0.76 ± 0.08 and α ( μ − ) = 0.83 ± 0.06.
No description provided.
Numbers of events per 10**6 incident PI-.
In the first holographic bubble chamber experiment — the HOBC experiment — we have accumulated a total of 40000 holograms with particle interactions. We have determined the total charm pair cross section inpN collisions to be 23.3−7.7+10 μb and 3.6−1.7+2.3 μb for 360 and 200 GeV/c incident protons respectively. We have assumed a linear dependence of the cross section on the atomic number of the target. This experiment has demonstrated the feasibility of holographic recording in small bubble chambers. Assuming that the charm cross section can be described by the standard QCD factorized expression with gluon fusion and quark-antiquark annihilation, we have used our measured charm cross sections with other measurements to determine the effective charmed quark mass to be 1.8−0.35+0.25 GeV/c2. TheK factor, which describes the importance of the higher order corrections, is calculated to be 9.8−6.9+12.5 (See noted added in proof.)
No description provided.
B B production in π − -uranium interactions has been observed at 320 GeV beam energy looking at events with three muons in the final state. The cross section is found to be σ B B = 4.5±1.4±1.4 nb per nucleon (for a linear A -dependence) or σ B B = 17.6±5.5±5.5 nb per nucleon (assuming A 0.75 dependence). An estimate of x F distribution is given.
BEAUTY INCLUSIVE SPECTRA WAS ASSUMED TO BE E*D(SIG)/D(X)/D(PT**2) = EXP(-0.9*PT**2)*(1-ABS(X))**A. THE BEST FIT FOR A IS A = 2.5.
ASSUME A**.75 DEPENDENCE.
No description provided.
The ratio of the branching fractions for p p →K + K − and p p →π + π − was determined with the CPLEAR detector, by stopping antiprotons in a gaseous hydrogen target at 15 bar pressure. It was found to be BR(K + K − )/BR( π + π − )=0.205± 0.016. The fraction of P-wave annihilation at rest at this target density was deduced to be (38±9)%.
CONST is the fraction of P-wave annihilation in gaseous hydrogen at pressu re of 15 bar. In the SIG/SIG the statistical and systematic errors are added qu adratically.
A sample of 29 gu + υ + 35 υ − υ − coming from B B decay have been observed in π -U interactions at 320 GeV energy. The experimental distributions and the total cross section are found to be in good agreement with QCD predictions. The effect of B 0 B 0 mixing is discussed.
BEAUTY INCLUSIVE SPECTRA WAS ASSUMED MN FORM : E*D(SIG)/D(X)/D(PT**2) = EXP(-0.9*PT**2)*(1-ABS(X))**A. THE BEST FIT FOR A IS A = 2.5.
No description provided.
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 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.
An experimental investigation of the structure of identified quark and gluon jets is presented. Observables related to both the global and internal structure of jets are measured; this allows for test
The measured jet broadening distributions (B) in quark and gluon jets seperately.
Measured distributions of -LN(Y2), where Y2 is the differential one-subjet rate, that is the value of the subjet scale parameter where 2 jets appear from the single jet.
The mean subjet multiplicity (-1) for gluon jets and quark jets for different values of the subject resolution parameter Y0.
The three polarization tensor components of the deuteron produced in the H( p , d )π + reaction have been measured for the first time. The experiment was performed using a vertically polarized proton beam produced by the SATURNE accelerator. The deuteron polarization was measured with the POLDER polarimeter. The three polarizing powers t 20 00 , t 21 00 and t 22 00 and the three spin-transfer observables t 20 11 , t 22 11 and t 22 11 have been extracted at a proton kinetic energy of 580 MeV over a wide angular range and at two fixed center-of-mass angles, 132° and 151°, between 800 and 1300 MeV. The six observables, calculated in the C.M. helicity frame, have been compared with predictions of the most refined partial-wave analyses and also with the predictions of a theoretical coupled-channel model which includes the NN-NΔ transition. The comparison between the data and the theory/partial-wave analyses shows some discrepancies which get worse with increasing proton energy. Adding these data to the world database should improve significantly future partial-wave analyses. The A y 0 analyzing power has also been measured over the same kinematical range. The partial-wave analysis predictions are in good agreement with this observable.
No description provided.
No description provided.
No description provided.
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