Experimental data are presented on deuteron production in the target fragmentation region for 250 GeV/c π+ interactions with Al and Au nuclei, and compared with analogous data on proton production. Indications are observed for narrow structures in the (dπ-) effective mass system at ∼2.04 and ∼2.08 GeV.
Number of weighted events as a function of number of forward produced deuterons.
Number of weighted events as a function of number of forward produced deuterons.
Mean deuteron multiplicity.
Measurements are reported of inclusive production of π0-mesons in the beam fragmentation region in γp, πp andKp collisions. Results include the ratio of π0 production inKp and πp collisions, showing reduced production from fragmentation of theK-meson, and the ratio of π0 production in photon and hadron collisions which shows agreement with modified Vector Meson Dominance at lowPT, and departures at higherPT signalling the onset of direct photon reactions. The pattern of departure from Feynman scaling at highPT points to a contribution of hard parton-parton collisions in both γp and πp collisions.
No description provided.
No description provided.
No description provided.
We present a study of energy-energy correlations based on 83 000 hadronic Z 0 decays. From this data we determine the strong coupling constant α s to second order QCD: α s (91.2 GeV)=0.121±0.004(exp.)±0.002(hadr.) −0.006 +0.009 (scale)±0.006(theor.) from the energy-energy correlation and α s (91.2 GeV)=0.115±0.004(exp.) −0.004 +0.007 (hadr.) −0.000 +0.002 (scale) −0.005 +0.003 (theor.) from its asymmetry using a renormalization scale μ 1 =0.1 s . The first error (exp.) is the systematic experimental uncertainly, the statistical error is negligible. The other errors are due to hadronization (hadr.), renormalization scale (scale) uncertainties, and differences between the calculated second order corrections (theor.).
Statistical errors are equal to or less than 0.6 pct in each bin. There is also a 4 pct systematic uncertainty.
ALPHA_S from the EEC measurement.. The first error given is the experimental error which is mainly the overall systematic uncertainty: the first (DSYS) error is due to hadronization, the second to the renormalization scale, and the third differences between the calculated and second order corrections.
ALPHA_S from the AEEC measurement.. The first error given is the experimental error which is mainly the overall systematic uncertainty: the first (DSYS) error is due to hadronization, the second to the renormalization scale, and the third differences between the calculated and second order corrections.
Parity nonconservation in proton-proton scattering has been studied by measuring the angle-integrated longitudinal analyzing power A z . We found A z (13.6 MeV)=(−1.5±0.5)×10 −7 . The error includes uncertainties due to statistics and corrections, as well as upper limits on systematic effects. The experimental result is discussed with respect to recent theoretical calculations.
No description provided.
None
No description provided.
Production of multi-strange baryons and antibaryons is expected to be a useful indicator in the search for Quark-Gluon Plasma formation. Production of Ξ − and Ξ − has been observed for the first time in ultra-relativistic heavy ion interactions by the WA85 Experiment. We describe the procedure used to select these cascade candidates and show that Ξ − and Ξ − decays can be identified. Preliminary ratios of Ξ/Ξ production in sulphur-tungsten and proton-tungsten interactions are also presented.
PRODUCTION AT CENTRAL RAPIDITY. 123 XI- AND 53 XIBAR+ CANDIDATES.
PRODUCTION AT CENTRAL RAPIDITY. 82 XI- AND 22 XIBAR+ CANDIDATES.
None
No description provided.
No description provided.
No description provided.
The production ofπ0 andη mesons has been studied in the reactions20Ne +Al at 350 MeV/u and40Ar + Ca at 1.0 GeV/u. Rapidity distributions and transverse momentum spectra have been measured and are compared to thermal distributions.
THE SPECTRUM (1/PT)*D(SIG)/D(PT) HAS BEEN FITTED BY A THERMAL DISTRIBUTION SQRT(MT)*EXP(-SLOPE*MT).
THE SPECTRUM (1/PT)*D(SIG)/D(PT) HAS BEEN FITTED BY A THERMAL DISTRIBUTION SQRT(MT)*EXP(-SLOPE*MT).
We are reporting an improved determination of the electroweak mixing angle sin 2 Θ w from the ratio of ν μ e to ν μ e scattering cross sections. The CHARM II detector was exposed to neutrino and antineutrino wide band beams at the 450 GeV CERN SPS. Including new data collected in 1989 we have obtained 1316 ± 56 ν μ e and 1453 ± 62 ν μ e events. From the ratio of the visible cross sections we determined sin 2 Θ 0 =0.239 ± 0.009(stat) ± 0.007(syst) without radiative corrections and g V e g A e =0.047 ± 0.046 . Combining this last result with recent results on g A e at LEP we obtain g V e = −0.023 ± 0.023.
Systematic error presented includes error from flux normalization 'F'=1.030+- 0.022, no detaled description of the other sources and of the combination pr ocedure.. 'F'.
Without radiative corrections, systematic error combined in quadrature fromconponents listed under SYSTEMATICS.
With radiative corrections as defined by Marciano-Sirlin scheme, see Phys.Rev.D22(1980)2695, Phys.Rev.Lett.46(1981)163, Phys.Rev.D29(1984)945, Phys.Rev.D31(1985)213E, Nucl.Phys.B217(1983)84. CENTRAL VALUE IS FOR M(TOP)=100 GEV, M(HIGGS)=100 GEV.
Experimental results obtained at the CERN Super Proton Synchrotron on the structure-function ratio F2n/F2p in the kinematic range 0.004
No description provided.
Forum