We have measured the polarization of $\Lambda$ hyperons produced inclusively by a $\Sigma^-$ beam of 340 GeV/c momentum in nuclear targets. From a sample of 9.5 millions of identified $\Lambda$ decays, polarizations were determined in the range $x_F \gt 0.1$ and $p_t\leq 1.6$ GeV/c . The polarization w.r.t. the production normal is mainly positive for $x_F \geq 0.3$. At fixed values of $x_F$, it increases with $p_t$ to a maximum between $p_t = 0.5$ and $p_t = 1$ GeV/c , and then decreases to zero or even negative values, in sharp contrast to the plateau above $p_t = 1$ GeV/c observed in inclusive $\Lambda$ production by protons.
Measured values of the LAMBDA polarization as a function of PT in the XL range 0.1 to 0.2.
Measured values of the LAMBDA polarization as a function of PT in the XL range 0.2 to 0.3.
Measured values of the LAMBDA polarization as a function of PT in the XL range 0.3 to 0.4.
We report the first observation of the Xi- pi+ decay mode of the Xi0(1690), confirming the existence of this resonance. The Xi0(1690) were produced by Sigma- of 345 Gev/c mean momentum in copper and carbon targets. The mass and width are close to those observed earlier for the Xi-(1690) in the Lambda K- decay channel. The product of inclusive production cross section and branching ratio is given relative to that of the Xi0(1530).
The cross setion times branching ratio.
The differential cross sections for they+ p-- n + 7T+ process were measured for y-quantum energies 200, 205 and 210 MeV and meson emission angles 16, 24, 36, 44, 56, 64, 76, 84, 96, 104, 116, 124, 136, 144 and 156° relative to the photon beam in the laboratory system. A phenomenological analysis of the results is carried out and some multipole charged-meson photoproduction amplitudes are determined. The results are compared with the predictions of the dispersion-relation theory.
Axis error includes +- 4.8/4.8 contribution.
We present a comprehensive study of the inclusive production of V 0 V 0 pairs (V 0 =Lambda, Lambda-bar or K S ) by Sigma - and pi - of 340 GeV/ c momentum and neutrons of 260 GeV/ c mean momentum in copper and carbon targets. In particular, the de pendence of the x F spectra on the combination of beam-particle and produced V 0 V 0 pair is investigated and compared to predictions obtained from PYTHIA and QSGM calculations. The data and these predictions differ in many details, the agreement can at b est be termed as qualitative. A signal from decays of the tensor meson f? 2 (1525) was observed in the K S K S mass distribution and inclusive production cross sections were measured. No signal was found from the double-strange H-dibaryon decaying to Lamb daLambda.
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We report on a measurement of the inclusive cross sections of $\Lambda$ , $\overline\Lambda$ , K 0
Total inclusive hyperon production cross sections per nucleon for the SIGMA- beam, and the exponent in the cross section parametrization of the form A**POWER.
Total inclusive hyperon production cross sections per nucleon for the PI- beam, and the exponent in the cross section parametrization of the form A**POWER.
Total inclusive hyperon production cross sections per nucleon for the Neutron beam, and the exponent in the cross section parametrization of the form A**POWER.
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Total inclusive production cross sections per nucleon for the SIGMA- beam, and the exponent in the cross section parametrization of the form A**POWER.
Inclusive SIGMA(1660) production cross sections, times the < LAMBDA PI> branching ratio, in the XL range 0.3 to 1.0 for the SIGMA- beam on the Copper target.
Inclusive SIGMA(1660) production cross sections, times the < LAMBDA PI> branching ratio, in the XL range 0.3 to 1.0 for the SIGMA- beam on the Carbon target.
The production of charmed particles by Sigma- of 340 Gev/c momentum was studied in the hyperon beam experiment WA89 at the CERN-SPS, using the Omega-spectrometer. In two data-taking periods in 1993 and 1994 an integrated luminosity of 1600 microb^-1 on copper and carbon targets was recorded. From the reconstruction of 930 +- 90 charm particle decays in 10 decay channels production cross sections for D, antiD, Ds and Lambdac were determined in the region xF>0. Assuming an A^1 dependence of the cross section on the nucleon number, we calculate a total ccbar production cross section of sigma(x_F > 0) = 5.3+- 0.4(stat)+-1.0(syst)+1.0(Xi_c) microb per nucleon. The last term is an upper limit on the unknown contribution from charmed-strange baryon production.
Fits to the DSIG/DXL and DSIG/DPT**2 distributions in the range XL > 0. Theerrors shown are statistical only.. The fits are of the following form:. DSIG/DXL : Const*(1-X)**N. DSIG/DPT**2 : Const*EXP(-B*PT**2).
The production cross sections for anti-charmed and charmed hadrons in the range XL > 0. The Errors are statistical only.
The total CQUARK+CQUARKBAR cross section in the range XL > obtained as the weighted average of the sum of all the measured contributions to the charmed andanti-charmed hadron production in the previous table. second systematic (DSYS) error is due to the uncertainty in the contribution of XI/C production to the cross section.
We report on a measurement of the differential and total cross sections of inclusive production of Xi resonances in Sigma - nucleus collisions at 345 GeV/c.
Feynman X distribution (times BR) per nucleon for XI(1820) and XI(1950) production. The quoted errors are statistical.
PT**2 distribution (times BR) per nucleon for XI(1530) and XI(1890) production. The quoted errors are statistical.
Total cross section per nucleus and per nucleon. The quoted errors are statistical.
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