The total proton-proton cross section (excluding Coulomb scattering) has been measured at energies from 410 Mev up to 2.6 Bev, using external beams from the Cosmotron. Fast counting equipment was used to measure the attenuation of the beams through polyethylene, carbon, and liquid H2 absorbers. At each energy E, σp−p(E, Ω) was measured as a function of the solid angle Ω subtended by the rear counter at the center of the absorber. The total cross section σp−p was obtained by a least squares straight line extrapolation to Ω=0. The measured σp−p as a function of energy rises sharply from 26.5 mb at 410 Mev to 47.8 mb at 830 Mev and then remains approximately constant out to 1.4 Bev, above which energy it decreases gradually to about 42 mb at 2.6 Bev. Using the same equipment and procedure, we have also measured the D2O-H2O difference cross section, called "σp−n," for protons over the same energy range. From a comparison of "σp−n," and σp−p, with the n−p and n−d measurements of Coor et al. at 1.4 Bev, it is apparent that one nucleon is "shielded" by the other in the deuteron. This effect is not present at energies below 410 Mev. Comparing the measured p−p and "p−n" (corrected) cross sections with the results of other high-energy experiments, one may infer the following conclusions: (1) The sharp rise in σp−p from 400 to 800 Mev results from increasing single pion production, which may proceed through the T=32, J=32 excited nucleon state. (2) Above 1 Bev the inelastic (meson production) p−p cross section appears to be approximately saturated at 27-29 mb. (3) The rise in cross section for n−p interaction in the T=0 state, associated with the rise in double pion production, implies that double meson production also proceeds through the T=32 nucleon state. (4) The probable equality of σp−d and σn−d at 1.4 Bev implies the validity of charge symmetry at this energy.
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Measurements have been made of the total cross sections σ(p−p) and σ(p−d) over the laboratory momentum range 1.1 to 8 GeV/c, with relative errors of 0.1%. The absolute accuracies of these cross sections are limited to 0.3% by lack of information which will allow the Coulomb-nuclear interference to be calculated accurately. Values of the total cross sections σ(p−n) and σ(I=0) are deduced by assuming the Glauber correction. Structure is observed in σ(p−p) near a mass value of 2.75 GeV/c2; its interpretation is discussed. σ(I=0) rises rapidly in the range 2.3 to 2.9 GeV/c2, and this is attributed to the onset of strong inelastic scattering.
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Total cross sections of π+ and π− mesons on protons and deuterons have been measured in a transmission experiment to relative accuracies of ±0.2% over the laboratory momentum range 0.46-2.67 GeV/c. The systematic error is estimated to be about ±0.5% over most of the range, increasing to about ±2% near both ends. Data have been obtained at momentum intervals of 25-50 MeV/c with a momentum resolution of ±0.6%. No new structure is observed in the π±p total cross sections, but results differ in several details from previous experiments. From 1-2 GeV/c, where systematic erros are the smallest, the total cross section of π− mesons on deuterons is found to be consistently higher than that of π+ mesons by (1.3±0.3)%; about half of this difference may be understood in terms of Coulomb-barrier effects. The πd and πN total cross sections are used to check the validity of the Glauber theory. Substantial disagreements (up to 2 mb) are observed, and the conclusion is drawn that the Glauber theory is inadequate in this momentum range.
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The total cross sections for νμn and νμp charged-current interactions and their ratio R=σT(νn)σT(νp) have been measured as a function of neutrino energy from 0.4 to 10 GeV. The experiment is performed using the BNL 7-foot deuterium bubble chamber exposed to the Alternating Gradient Synchrotron wide-band neutrino beam. The absolute values of the cross sections are normalized to the quasielastic scattering (νμn→μ−p) cross section. Above 1.6 GeV the data are consistent with the quark-parton model. We find that σT(νn)Eν=(1.07±0.05)×10−38, σT(νp)Eν=(0.54±0.04)×10−38, and σT(νN)Eν=(0.80±0.03)×10−38 cm2/GeV for 〈Eν〉=3.2 GeV, and R=1.95±0.10 for 〈Eν〉=3.7 GeV.
Axis error includes +- 0.0/0.0 contribution (?////SYSTEMATIC ERROR NOT GIVENNEUTRAL CURRENT AND NEUTRAL PARTICLES INDUCED REACTIONS, RESCATTERING IN DEUTERIUM).
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We report measurements of kaon electroproduction from hydrogen and deuterium targets carried out at the Wilson Synchrotron Laboratory at Cornell University. The reactions γVp→K+X0, K+Γ, and K+Σ0 were studied in the kinematic region 2.15≤W≤3.1 GeV and 1.2<Q2<4.0 GeV2 as a function of Q2, W, and ω. The K+Σ0 cross sections fall much more rapidly with increasing Q2 than the K+Λ cross sections so that K+Σ0KΛ→0 as Q2 increases.
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FIRST 11 DATA POINTS ARE FROM THE PRESENT EXPERIMENT. THE NEXT 4 DATA POINTS ARE HARVARD-CORNELL DATA: BEBEK ET AL., PRL 32, 21 (1974). THE LAST 8 DATA POINTS ARE CEA DATA: BROWN ET AL., PRL 28, 1086 (1972).
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The total and elastic cross sections for antineutrons on protons have been measured for antineutron momenta from 0.5 to 2.5 GeV/c. The results are in agreement with previous p¯p data at these momenta.
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Cross sections for ρ0 electroproduction measured in a streamer-chamber experiment are separated into elastic (ep→epρ0) and inelastic production channels. For the elastic channel, the total cross section and t dependence are presented. For the inelastic channel (1σ)dσdz, (1σ)dσdpT2, and a density matrix element are shown and compared to quark-parton-model predictions. The ratio of ρ0 to direct π0 production is found to be 2.0±0.5±0.3, where the first error is statistical, and the second error is systematic.
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We present new high statistics data on hadron production in photon-photon reactions. The data are analyzed in terms of an electron-photon scattering formalism. The dependence of the total cross section of Q 2 , the four-momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector-Meson Dominance and the quark model.
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DEPENDENCE ON VISIBLE HADRONIC INVARIANT MASS.
Data read from graph.
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