The e + e − → p p cross section has been measured between 1925 and 2180 MeV. About 50 p p events were detected. The total cross section decreases from 1.31 ± 0.4 nb near 1937 MeV to 0.55 ± 0.2 nb near 2135 MeV. The proton form factors | G E | 2 and | G M | 2 , assumed identical, decrease from 0.15 ± 0.05 to 0.043 ± 0.015. They are an order of magnitude higher than predicted by the well-known dipole fit. The energy range has been scanned in steps of about 2 MeV. No significant structure was found in this p p sample.
TOTAL CROSS SECTION ASSUMING ISOTROPIC PRODUCTION. RADIATIVE CORRECTIONS CALCULATED USING PEAKING APPROXIMATION (ABOUT 20 PCT). AUTHORS ALSO QUOTE RESULTS FOR LIMITED (COSMIC RAY FREE) ACCEPTANCE AS A CHECK. FORM FACTOR DERIVED ASSUMING ELECTRIC AND MAGNETIC FORM FACTORS EQUAL IN MAGNITUDE.
Measurements of recognized π0 production in p-Be collisions for 0.1<X⊥<0.5 and −0.8<XF<0.0 at 200, 300, and 400 GeV/c are presented. These invariant cross sections are fitted by Edσdp3=A(1−XR)MP⊥−N over this range of X⊥ and XF with M=4.88±0.14 and N=8.90±0.10 independent of energy. No significant evidence for breaking of this scaling is observed over this large kinematic region at these energies.
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Cross sections and charged multiplicity distributions forK+p interactions at 70 GeV/c are presented and compared withK+p data at other energies. Comparisons are also made with available π+p,pp, andK−p data.
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We present data on dimuon production by 16 GeV π + and π − beams on a Cu target. From the data we evaluate, for π − N collisions, the fraction of dimuon events that originate from the annihilation process q q ̄ → μ + μ − . Using this information the experimentally determined cross section for the process q q ̄ → μ + μ − is observed to be in agreement with the Drell-Yan model over a wide range of incident energies. The observed deviations from exact scaling are of the order predicted by QCD calculations for the Q 2 -dependence of the nucleon and the pion structure function.
CROSS SECTIONS ARE PER COPPER NUCLEUS.
CROSS SECTIONS ARE PER COPPER NUCLEUS.
We present a systematic investigation of channel cross sections in K − p interactions at 32 GeV/ c . The energy dependence of these cross sections is discussed. We also investigate a few non-diffractive two-body reactions. The total cross sections of the two reactions K − p → K ∗− (890) p and K − p → K ∗− (1420) p have a markedly different energy behaviour. There is clear evidence for the reaction K − p → K ∗0 (890) N 0 (1688) ; its differnttial cross section exhibits a sharp forward slope of 24 ± 3 GeV −2 .
FROM AK0 P PI- FINAL STATE.
DOUBLE RESONANCE CHANNEL CROSS SECTIONS FROM BREIT-WIGNER FIT CORRECTED FOR BACKGROUND AND DIFFRACTIVE PROCESSES.
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Measurements have been made of the inclusive scattering of 96, 147, and 219 GeV muons from hydrogen, and of 147 GeV muons from deuterium. Results are presented for the nucleon structure function F2(x,Q2) [≡νW2(x,Q2)] for 10<ν<200 GeV and 0.2<Q2<80 GeV2. The value of F2 rises with Q2 at small x, and falls with Q2 at large x, in agreement with the ideas of quantum chromodynamics. An average value of the ratio σLσT≡R=0.52±0.35 has been obtained for the region 0.003<x<0.10 and 0.4<Q2<30 GeV2. The values of F2 from this experiment have been combined with those from other charged-lepton scattering experiments to determine moments of the structure functions. The variation with Q2 of these moments is used to derive values for Λ, taking into account corrections up to second order in αs. The fit to the data is very good.
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Data on inclusive jet production in the transverse-momentum (p⊥) range 0-8 GeV/c for 200-GeV/c p, π−, π+, K−, K+, and p¯ incident on a hydrogen target are presented. The jet cross section is fully corrected for losses and biases, and compared with the predictions of a model based on quantum chromodynamics. Both the absolute cross section and the inclusive charged-particle distributions inside and outside the jet are in qualitative agreement with the model.
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Final data on topological cross sections are presented. Inclusive single particle distributions for the reactionsK+p→ π±X at 32 GeV/c are discussed and compared with data at lower energies. Early scaling in the fragmentation regions is confirmed, while cross sections in th central region continue to rise with energy even faster than inpp interactions. Thex-andpT-dependence of the π+/π− ratio inK+p interactions is discussed and a comparison of reactionsK+p→ π±X andK−p→ π±X at 32 GeV/c is made in the context of constituent models. We also present transverse momentum distributions, show prominent seagull effects and study how they are influenced by resonance production.
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The ratio of π - to π + electroproduction cross sections from deuterium has been measured in the resonance region, at a four-momentum transfer squared close to −1.0 (GeV/ c ) 2 . Results in the forward direction are presented and a comparison is made with predictions based on SU(6) W and the Melosh transformation.
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The differential and channel cross sections have been measured for the reactions K L 0 p → K S 0 p and K L 0 p → Λ 0 π + in nine energy intervals in the c.m. range 1605 to 1910 MeV. The regeneration reaction is a combination of the KN amplitudes (with I = 0 and 1) and the K N amplitude ( I = 1) and is very sensitive to the various KN phase-shift solutions, some of which show an exotic I = 0, P 1 resonance. Our results have been expressed in terms of frequency distributions and cross sections, normalised by the Λ 0 π + reaction. These results have been compared with the predictions of various partial-wave analyses. Qualitatively we can eliminate the P 1 non-resonant solution, though no solution correctly predicts our results.
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