Transmission measurements in good and poor geometry have been performed at the Brookhaven Cosmotron to measure the total and absorption cross sections of several nuclei for neutrons in the Bev energy range. The neutrons are produced by bombarding a Be target with 2.2-Bev protons. The neutron detector requires the incident particle to pass an anticoincidence counter and produce in an aluminum radiator a charged particle that will traverse a fourfold scintillation telescope containing 6 in. of lead. Contribution of neutrons below 800 Mev are believed small. The angular distribution of neutrons from the target is sharply peaked forward with a half-width of 6°. The integral angular distributions of diffraction scattered neutrons from C, Cu, and Pb are measured by varying the detector geometry. The angular half-width of these distributions indicates a mean effective neutron energy of 1.4±0.2 Bev. The total cross sections σH and σD−σH are measured by attenuation differences in good geometry of CH2-C and D2O-H2O, with the result: σH=42.4±1.8 mb, σD−σH=42.2±1.8 mb. The cross sections of eight elements from Be to U are measured in good and poor geometry, and the following values of the total and absorption cross sections are deduced (in units of millibrans): Experimental errors are about 3 percent in σtotal and 5 percent in σabsorption. An interpretation of these cross sections is given in terms of optical model parameters for two extreme nuclear density distributions: uniform (radius R) and Gaussian [ρ=ρ0exp−(ra)2]. The absorption cross-section data are well fitted with R=1.28A13 or a=0.32+0.62A13 in units of 10−13 cm. A nuclear density distribution intermediate between uniform and Gaussian will make the present results consistent with the recent electromagnetic radii.
'ALL'.
No description provided.
Twenty-nine proton-proton differential elastic cross sections for lab momenta p0 from 11 to 31.8 BeV/c, at four-momentum transfers squared, −t, from 2.3 to 24.4 (BeV/c)2, have been measured at the Brookhaven alternating gradient synchrotron. The circulating proton beam impinged upon a thin CH2 internal target. Both scattered protons from p−p elastic events were detected by scintillation-counter telescopes which were placed downstream from deflection magnets set at the appropriate angles to the incident beam. The angular correlation of the protons, their momenta, and the coplanarity of the events were determined by the detection system. The results show that at high momentum transfers the differential cross section, dσdt, depends strongly upon the energy; for −t=10 (BeV/c)2, the value of dσdt at p0=30 BeV/c is smaller by a factor∼1000 than at p0=10 BeV/c. At all energies, dσdt falls rapidly with increasing |t| for scattering angles up to about 65° (c.m.), while in the range from 65 to 90° the cross section falls only by a factor of about 2. The smallest cross section measured was 9×10−37 cm2 sr−1 (c.m.), at p0=31.8 BeV/c and −t=20.4 (BeV/c)2; this is about 3×10−12 of the zero-degree cross section at the same energy.
'1'. '2'.
Antiproton-proton elastic scattering has been measured at 3.55 GeV/ c in the c.m. angular range from 20° to 77° and from 109° to 160°. Forward elastic scattering shows a structure near t = −0.5 (GeV/ c ) 2 . In the backward region two events are observed.
'1'.
The angular distributions of K+p and π+p backward elastic scattering have been measured at 5.2 and 6.9 GeV/c. Backward π-p and K-p elastic scattering were studied at 6.9 GeV/c. Backward peaks are observed in K+p scattering with an energy dependence of the form s−4.
No description provided.
The differential cross section for π + p elastic scattering at 895, 945, 995 and 1040 MeV/ c has been measured in a hydrogen bubble chamber. The results are in good agreement with previous measurements using counter techniques except at extreme backward angles where significantly lower cross sections are obtained.
No description provided.
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We present results of measurements of the differential cross sections for the following elastic-scattering reactions: (i) π + p at 5.2 and 7.0 GeV/ c in the range −1 < u < 0.02 (GeV/ c ) 2 , (ii) π − p at 7.0 GeV/ c in the range −0.7 < u < 0.05 (GeV/ c ) 2 , (iii) K + p at 5.2 and 7.0 GeV/ c in the ranges −1 < t < −0.01 (GeV/ c ) 2 and −1 < u < 0 (GeV/ c ) 2 , and K − p at 7.0 GeV/ c in the range −1 < u < 0 (GeV/ c ) 2 .
No description provided.
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SIDE GEOMETRY.
Cross sections are presented for the K + p interacttions with 2, 3, 4 and 5 particles in the final state for incident momenta between 2.1 and 2.7 GeV/c. The results are compared with those from other experiments at nearby momenta.
Axis error includes +- 0.0/0.0 contribution (?////).
The energy dependence of backward π+p elastic scattering has been measured for incident π momenta 2.0-6.0 GeV/c in steps of typically 100 MeV/c. Values are presented for both the differential cross section extrapolated to 180° and the slope of the backward peak as a function of momentum. In the s channel we see the effects of the established Δ++ resonances and evidence for the Δ(3230). Also, the data show the existence of a negative-parity Δ resonance with mass ∼2200 MeV/c2.
No description provided.
Results are given from a study of 15 518 events of the reaction K + d → K + π − pp. The K + π − spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K + π − → K + π − elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier K π scattering studies using the reaction K + p → K + π − Δ ++ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.
No description provided.
Total cross sections of π± and K± on protons and deuterons have been measured at 50, 100, 150, and 200 GeV/c. All of the cross sections rise with increasing momentum.
No description provided.
PARTICLE-ANTIPARTICLE CROSS SECTION DIFFERENCES - SOME COMMON ERRORS CANCEL.
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