We have studied the production of charged D ∗ mesons in e + e − annihilation at an average center-of-mass energy of 58.0 GeV. Charged D ∗ mesons were identified using two independent methods; the mass-difference method and the detection of the low transverse-momentum pion. The forward-backward asymmetry of the charm quark production was measured to be A c = −0.61±0.13(stat.)±0.08(syst.). The cross section of inclusive D ∗ production was found to be σ(e + e − →D ∗ ± +X) = 24.5 ± 5.3 ( stat. )±3.0( syst. ) pb. If we assume the standard model prediction for the charm quark production, we obtain the branching ratio for the charm quark to produce a charged D ∗ meson to be Br (c→D ∗+ + X) = (22±5( stat. )±3( syst. ))% .
We have measured the inclusive production of J ψ in 16 and 22 GeV π − copper collisions in a wide aperture magnetic spectrometer. The cross section per Cu nucleus for x > 0 corrected for branching ratio is 64 ± 38 nb at 16 GeV and 196 ± 38 nb at 22 GeV. As threshold is approached, the mean values of the Feynman x distribution increase and the cross section for J ψ production drops steeply. This can be understood in terms of the quark-fusion model where the antiquark content of the pion makes an increasingly significant contribution as M 2 s increases.
We have studied inclusive KS0, Λ, and Λ¯ production in π+d interactions at 24 GeV/c. The observed cross sections are 2.5±0.13 mb for KS0, 1.62±0.09 mb for Λ, and 0.12±0.02 mb for Λ¯. Longitudinal- and transverse-momentum distributions of the produced particles are presented. The average charged multiplicities of the system associated with a KS0 or with a Λ are presented and discussed. A nonzero average Λ polarization (-0.10±0.03) is observed. The x distribution of the backward (forward) KS0 and Λ produced in the reaction are in agreement with the x distribution of valence quarks in nucleons in nuclear target (pion beam), as predicted by the quark-recombination model of particle production applied to nuclear targets.
Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).
Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).
Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).
The intermediate and forward gamma detectors of EHS are used to reconstructπ°'s produced by 360 GeV/cpp interactions in the Rapid Cycling Bubble Chamber (RCBC). Using thepp forwardbackward symmetry, the inclusiveπ° production cross section is obtainedσπ°=(132±11) mb. The averageπ° multiplicity is determined as a function of the charged particle multiplicity. The (1−x) dependence is given for differentpT regions.
No description provided.
No description provided.
Axis error includes +- 4/4 contribution.
Using the VENUS detector at TRISTAN we have investigated the charm-quark production by detecting D*+ - mesons in the two-photon process of e+et - collisions. The study has confirmed that the charm-quark production rate is larger than that predicted from direct cc̅ production alone. The distribution of the transverse momentum of the D*+ t- mesons and the forward energy flow associated with the D*+ - production suggest that the main part of the observed excess comes from the contribution of a resolved photon process.
The inclusive production of π ± mesons in e + e − annihilation has been measured at c.m. energies of 14, 22 and 34 GeV for pion momenta between 0.3 ans 10 GeV/ c . The fraction of pions among the charged hadrons is above 90% at 0.4 GeV/ c and decreases to about 50% at high momenta. The scaled cross sections ( s β ) d σ d x at 14, 22 and 34 GeV as well as the 5.2 GeV data from DASP have a rather similar x dependence. After integration over the x range from 0.2 to 0.6 the cross sections indicate a monotonic decrease with increasing centre-of-mass energy.
Inclusive K0K¯0, Λ0, and Λ¯0 cross sections have been determined using a 292-event/mb exposure of the hydrogen-filled 15-foot bubble chamber at Fermilab. From the invariant-mass distributions of V0π± pairs we find that σ(K*±(890))=4.4±1.4 mb, σ(Σ*±(1385))=0.54±0.40 mb, and σ(Σ¯*±(1385))=0.45±0.34 mb. It is estimated that 0.32 ± 0.11 of K0K¯0's, 0.21 ± 0.16 of Λ's, and 0.96 ± 0.75 of Λ¯'s originate from decays of K*(890) and Σ*(1385), respectively.
No description provided.
No description provided.
No description provided.
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Total inclusive production cross sections for the SIGMA- beam on the Coppertarget.
Total inclusive production cross sections for the SIGMA- beam on the Carbontarget.
Total inclusive production cross sections per nucleon for the SIGMA- beam, and the exponent in the cross section parametrization of the form A**POWER.
The differential cross sections for antiproton elastic scattering on 4 He at 192.8 MeV/ c are measured. The annihilation cross section σ a = (377.6 ± 8.0) mb, the elastic cross section σ el = (206.3 ± 6.6) mb and the total p 4 He interaction cross section σ tot = (583.9 ± 10.4) mb are determined. The ratio of the real to imaginary part of the forward p 4 He amplitude is found: π =−0.17± 0.33 0.24 . Partial wave analysis reveals that the S, P and D waves are essential in this energy region.
Charged prong multiplicity distributions in pbar HE annihilation.
Mean charged particle multiplicity in pbar HE4 annihilations.
No description provided.
Results are presented for six nuclei from Be to Pb on the structure function ratios F 2 A / F 2 C ( x ) and their A dependence in deep inelastic muon scattering at 200 GeV incident muon energy. The data cover the kinematic range 0.01 < x < 0.8 with Q 2 ranging from 2 to 70 GeV 2 . The A dependence of nuclear structure function ratios is parametrised and compared to various models.
Additional normalisation error of 0.002 in the ratio.
Additional normalisation error of 0.002 in the ratio.
Additional normalisation error of 0.003 in the ratio.
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