The Λ-proton elastic scattering cross section has been measured between 1 and 17 GeV/c in a bubble chamber experiment. These are the first measurements of the elastic cross section for pΛ>5 GeV/c. The Λ's were produced by 25-GeV/c proton interactions in a platinum target. The cross section falls from 22 to 4 mb over the region. No significant polarization is observed.
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CORRECTION MADE FOR KL P --> KS P.
The differential cross sections of the elastic p p reaction have been measured at 1.2, 1.4, 1.8 and 2.6 GeV/ c incident p momentum. The measurements have been performed at the CERN PS using a system of multiwire proportional chambers. The angular region covers scattering angles from 0 to ∼200 mrad. Interference effects between the Coulomb and the nuclear amplitudes are used to derive the ratio of the real to imaginary part of the forward nuclear amplitude. These ratios are compared with theoretical predictions.
'MS'. 'TBIN'.
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'MS'. 'TBIN'.
Differential cross sections for the elastic scattering of negative kaons on protons are presented for 19 momenta between 1.732 GeV/ c and 2.466 GeV/ c . The general features of the cross sections are discussed.
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The differential cross sections for π + p elastic scattering at0.6, 1.0, 1.5, 2.0, GeV/ c for π - p at 1.0, 1.5, 2.0 GeV/ c , for K - p at 1.2, 1.8, 2.6 GeV/ c and for K - p at 0.9, 1.2, 1.4, 1.6, 1.8, 2.6 GeV/ c have been measured with an overall accuracy ofthe order of 1 to 2% in an electronics experiment over the angular region corresponding to momentum transfer t between 0.0005 and 0.10 GeV 2 . Making use of the interference effects between the Coulomb and the nuclear interaction, we have determined the magnitude and sign of the real part of the scattering amplitude near t = 0. The K ± p real parts have been used in a dispersion relation to derive the value of the KNΛ coupling constant.
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'TABLE'. 'BIN'.
'TABLE'. 'BIN'.
The differential cross sections of the combined elastic and break-up K − d reaction have been measured at 1.21, 1.42 and 2.61 GeV/ c incident K − momentum. The measurements have been performed at the CERN PS using multiwire proportional chambers. The values of the invariant momentum transfer t explored (0.0005<| t |<0.1 GeV 2 ) include the Coulomb-nuclear interference region. The differential cross sections have been analysed in the framework of the Glauber impact-parameter formalism. The observed interference effects have been used to derive the ratio of the real to imaginary part of the forward K − n nuclear amplitude.
SUM OF COHERENT AND BREAK-UP SCATTERING.
SUM OF COHERENT AND BREAK-UP SCATTERING.
SUM OF COHERENT AND BREAK-UP SCATTERING.
Measurements have been made of the differential cross section for p p elastic scattering over a c.m. angular range −0.95 ⩽ cos θ ∗ ⩽ 0.93 at 21 incident antiproton momenta between 0.69 GeV/ c and 2.43 GeV/ c (c.m. energy 1.96–2.58 GeV). About 10 5 events were obtained at each momentum. The results are discussed primarily in terms of the formation of s -channel resonances in the T and U mass regions, and within the context of the optical model of Frahn and Venter.
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Differential cross sections are presented for pion-proton elastic scattering in the angular range −0.6≳cosθc.m.≳−0.98 at 15 incident π+ momenta from 2.18−5.25 GeVc. The angular distributions rise steeply near 180° at all momenta. For laboratory momenta ≳2.75 GeVc they show a minimum at u≈−0.17 (GeVc)2 and a broad maximum near u≈−0.6 (GeVc)2. When the data are plotted versus s, for fixed u, a strong signal from the Δ(2420) resonance is observed. The data are compared with a direct-channel resonance model and with a Regge model which considers the exchange of the Nα, Nγ, and Δδ Regge trajectories. The qualitative success of both the direct-channel resonance model and the Regge model lends support to the concept of duality.
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We measured elastic-scattering angular distributions for π++p scattering at 1.5, 2.0, and 2.5 BeV/c using spark chambers to detect scattered pions and protons. A bump that decreases in amplitude with increasing momentum is observed in the backward hemisphere in the 1.5- and 2.0-BeV/c distributions, but is not observed in the 2.5-BeV/c distributions. It appears reasonable to attribute this phenomenon to the 1.45-BeV/c resonance observed in the π++p total cross section. The data are compared with π−+p data and are found to support the theoretical prediction that the scattering cross sections for both charge states should become equal at high energies. We fit the angular distributions with a power series in cosθ*, and compare the extrapolated values for the scattering cross section in the backward direction with the calculation of the neutron-exchange pole contribution to the cross section. The "elementary" neutron-pole term contribution is calculated to be 90 mb/sr at 2.0 BeV/c, in violent disagreement with the extrapolated value, ≈0.5 mb/sr.
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Measurements of the spin transfer parameters, K NN and K LL , at 500, 650 and 800 MeV are presented for the reaction p d → n pp at 0°. The data are useful input to the NN data base and indicate that the quasi-free charge exchange (CEX) reaction us a useful mechanism for producing neutrons with at least 40% polarization at energies as low as 500 MeV.
QUASI-FREE NP ELASTIC SCATTERING.
We present a series of numerical and statistical techniques for interpolating and combining ("amalgamating") data from meson-nucleon scattering experiments. These techniques have been extensively applied to πp elastic and charge-exchange differential-cross-section and polarization data in the resonance region. The amalgamation is done by fitting a momentum- and angle-dependent interpolating surface to the data over a moderately narrow momentum range, typically ∼150 MeV/c, using the interpolating surface to shift data in a narrower central momentum region into fixed angular bins at a predetermined central momentum, and then statistically combining the data in each bin. The fitting procedure takes into account normalization errors, momentum calibration errors, momentum resolution, electromagnetic corrections, threshold structure, and inconsistencies among the data. The full covariance matrix of the amalgamated data is calculated, including contributions of statistical error, systematic error, and interpolation error. Techniques are presented for extracting from the covariance matrix information on the collective statistical fluctuations which correlate the errors of the amalgamated data. These fluctuations are described in terms of "correlation vectors" which facilitate the use of the amalgamated data as input for resonance-region phenomenology.
No description provided.
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