K − p reactions have been studied at 13 different incident momenta between 1138 and 1434 MeV/ c . This interval corresponds to a mass of the K − p system varying from 1858 to 1993 MeV. About 300 000 photographs were taken in the 81 cm Saclay hydrogen bubble chamber exposed to a separated K − beam at the CERN proton-synchrotron. A total of about 44 000 events were analyzed, from which partial and differential cross sections were determined. Polarizations were obtained for the two-body reactions where the decay of the Λ or Σ hyperon allowed their measurement. Data for the two-body channels are presented here as well as for the main quasi-two-body reactions.
PARTIAL CROSS SECTIONS. DATA AT 1.305 TO 1.434 GEV/C FOR FINAL STATES K- P, K- P PI0 AND K- N PI+ COME FROM THE HAIFA GROUP, S. DADO ET AL.
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Experimental results are presented for the available channels in the 1.2 GeV/ c π + p interaction. An isobaric model with incoherent addition of the amplitudes is used to determine the π, Δ and N ∗ abundance rates in the π + π o p final state. The multipole parameters in the density matrix of the Δ ++ are determined as functions of its production angle.
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LEGENDRE POLYNOMIAL FIT USED TO CORRECT FOR ELASTIC EVENTS LOST FROM THE FORWARD BIN.
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The present data support a large anisotropy in accordance with phase shift predictions and in contrast to another recent experiment.
Measured deuteron angular distribution in the c.m. system. The errors shown are statistical only and there is an additional 10 PCT systematic uncertainty on the overall normalisation.
Legendre polynomial coefficients from a second order and fourth order fit.
Total cross section from second order fit.
The PS185 experiment at the CERN Low Energy Antiproton Ring (LEAR) has studied the reaction p ̄ p → \ ̄ gLΛ at several momenta. In this paper results from two runs with high statistics at 1.546 GeV/ c and 1.695 GeV/ c are described. Based on 4063 and 11362 analysed events, respectively, differential and integrated cross sections, polarizations and spin correlations are presented. The singlet fraction, extracted from the spin correlations, is consistent with zero at both momenta, showing that the \ ̄ gLΛ pairs are produced in a pure triplet state. A comparison of the decay asymmetry parameters of Λ and \ ̄ gL reduces the upper limits for the violation of the CP invariance for this system.
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THE BESTFIT WITH LMAX=3, HI2=1.204.
THE BESTFIT WITH LMAX=6, HI2=0.547.
The reaction p p → Λ Σ 0 together with its charge conjugate channel (c.c.) has been measured at LEAR. The incident p momentum was 1.695 GeV/ c , corresponding to an excess energy above threshold of 14.8 MeV. Results are given for the production cross section and the differential cross section as well as for the polarization. Comparisons are made with theoretical calculations and with the reaction p p → Λ Λ .
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A measurement of the total cross section for the reaction p p → π + π − has been performed for seven values of the incident momentum between 158 and 275 MeV/ c . The values obtained, if compared with previous results at higher momenta, agree with a 1/ß dependence. The differential cross section sssumed over the whole incident momentum range has also been measured and the result of a fit by Legendre polynomials is given.
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4*PI*LEG(L=0,P=4) = 1.07 +- 0.13 mb.
We present results from a high-momentum-resolution measurement of the π-p elastic differential and total cross-sections-at values of cos θ* between — 0.60 and 0.85 in the centre-of-mass system and at incident-beam momenta between 1.34GeV/c and 1.49 GeV/c—close to the X0 production threshold. There is no significant enhancement near the X0 production threshold. However, a small effect of ~ 3 standard deviations is present, having mass 1898.8 MeV and width ~5MeV, and appearing at an incident-pion momentum of 1435 MeV/c. In addition, a narrow ~ 5-standard-deviation effect atEc.m.= 1876 MeV appeared at an incident-pion momentum of 1389 MeV/c.
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In an experiment on K--proton interactions in a hydrogen bubble chamber, the cross sections and angular distributions have been studied for elastic and charge-exchange scattering, and charged sigma hyperon production in the momentum range 90-300 MeV/c. Good agreement is found with previous cross sections except for the charge-exchange channel where the new values are 60% larger. The production distributions of the charged sigma hyperons and the polarisation of the Sigma + hyperon clearly indicate that P waves are present down to about 150 MeV/c, much lower than previously reported.
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Data at two additional π+ momenta (1.28 and 1.41 GeVc) in the reaction π+p→Σ+K+ are presented. Charge independence is tested over the c.m. energy range 1.820 to 2.090 GeV; we used our data for the Σ+K+ channel and published data for the π−p→Σ0K0 and Σ−K+ channels.
No description provided.
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Total and differential cross sections are presented for proton-antiproton annihilation into π+π− and K+K− at six laboratory momenta between 686 and 1098 MeV/c. The two-pion final state displays moderate energy dependence in its differential cross section, but shows no evidence of any direct-channel resonances. In contrast, the two-kaon final state exhibits some behavior in the total and differential cross section suggestive of a possible direct-channel effect between 800 and 1000 MeV/c.
NOTE CUT EXCLUDES LARGE FORWARD CROSS SECTION.
LEGENDRE COEFFICIENTS NORMALIZED TO LEGN(L=0) = 0.5.
LEGENDRE COEFFICIENTS NORMALIZED TO LEGN(L=0) = 0.5.