A new determination of the u valence quark distribution function in the proton is obtained from the analysis of identified charged pions, kaons, protons and antiprotons produced in muon-proton and muon-deuteron scattering. The comparison with results obtained in inclusive deep inelastic lepton-nucleon scattering provides a further test of the quark-parton model. The u quark fragmentation functions into positive and negative pions, kaons, protons and antiprotons are also measured.
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Angular distributions of the analyzing powers for π+p→ and π−p→ elastic scattering have been measured in a single-scattering experiment employing a polarized proton target. Measurements were obtained for pion energies of 98, 139, 166, 215, and 263 MeV. The addition of these data to the existing πp database significantly reduces the uncertainties in all S and P phase shifts for πp reactions over the delta resonance.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 98 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 139 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 166 MeV.
We report measurements of the proton elastic form factors, G E p and G M p , extracted from electron scattering in the range 1⩽ Q 2 ⩽3(GeV/ c ) 2 . The uncertainties are <15% in G E p and <3% in G M p . The values of G E p are larger than indicated by most theoretical parameterizations, The ratio of Pauli and Dirac form factors, Q 2 F 2 p / F 1 p , is lower and demonstrates less Q 2 dependence than most of these parameterizations. Comparisons are made to theoretical models, including those based on perturbative QCD and vector-meson dominance.
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Results are presented of an analysis of the reaction pp→p f (K S 0 K ± π ∓ )p s at 300 GeV/ c . Clear f 1 (1285) and f 1 (1420) signals are seen. A spin-parity analysis shows that both are consistent with being 1 ++ states. The f 1 (1420) is found to decay only to K ∗ K and no 0 −+ or 1 +− waves are required to describe the data. The production of the f 1 (1285) as a function of energy is not the same as that for the f 1 (1420) whose cross section is found to be constant with energy.
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The total cross section for e + e − annihilation into hadrons has been measured for CM energies ranging from 50 to 57 GeV. We fit the predictions of the standard model to these measurements and those at lower energies. The mass of the Z 0 boson, M Z , and the QCD scale parameter, Λ MS , are derived from the fit. The results are M Z =88.6 −1.8 +2.0 GeV/ c 2 , and Λ MS =0.15 −0.11 +0.16 GeV .
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Inclusive production cross sections of charged pions on carbon, copper and bismuth by neutrons in the energy range of 300–580 MeV have been measured from 54° to 164°. The invariant cross sections can be expressed by Full-size image (<1 K) for the high-energy part of the pion spectra. The slope parameter exhibits a systematic variation with neutron energy and emission angle for the three targets. The dependence of the pion production on the target mass number varies strongly with pion energy and emission angle. The production cross sections are compared with the model of quasi-two-body scaling, the moving-source model and with intranuclear cascade calculations.
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We have measured the asymmetry of elastic pp scattering at small scattering angles (30–100 mrad) in the Coulomb-nuclear interference region, using the polarized proton beam of Saturne II, a segmented scintillator active target, and two telescopes of multiwire proportional chambers. Results are given at four energies — 940, 1000, 1320 and 2440 MeV-and are compared with phase-shift calculations.
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Correlations between target fragments were measured in α- and 14 N-induced reactions at 70, 250 and 800 MeV/u incident energies. The reaction mechanism is characterized by the linear momentum transfer and the excitation energy which were deduced from the kinematics and the mass distribution of the fission fragments. By selecting targets lighter than Th (Au and Ho) the yield from peripheral collisions is reduced by the increase in the fission barrier thus allowing events with the highest linear momentum transfer and excitation energy to be favoured. The results show that up to an incident energy of 800 MeV/u hot nuclei are formed which decay via normal binary fission. The linear momentum transfer is essentially constant over the covered energy range, but the excitation energy increases until the total incident energy is greater than 3 GeV. At this energy, independent of the projectile mass the fission probability of the heavy nuclei drops below 50%, while the emission of intermediate-mass fragments increases. The relative velocities between two intermediate-mass fragments exceed strongly the values of binary fission. Monte Carlo calculations show that the relative velocities between these fragments exclude a sequential emission from the recoil nucleus and support a simultaneous breakup mechanism.
SIG IS FISSION CROSS-SECTION CALCULATED WITH THE SOFT-SPHERE MODEL OF REF. PHYS.REV.C11 (1975) 1203.
SIG IS FISSION CROSS-SECTION CALCULATED WITH THE SOFT-SPHERE MODEL OF REF. PHYS.REV.C11 (1975) 1203.
SIG IS FISSION CROSS-SECTION CALCULATED WITH THE SOFT-SPHERE MODEL OF REF. PHYS.REV.C11 (1975) 1203.
This paper presents exhaustive, new data on the shower and compound multiplicity charactersties of 24 Mg-emulsion and 12 C-emulsion interactions at incident momentum of 4.5 GeV/ c per nucleon. A comparative study is made (whenever possible) with p-emulsion interaction data at the same incident momentum per nucleon. The linear dependences of different multplicities on shower and compound multiplicity, e.g., 〈 n i 〉 = a ij + k ij n j -( i ≠ j ), are also shown in this paper.
NUCLEUS IS EMULSION NIKFI-BR2.
NUCLEUS IS EMULSION NIKFI-BR2.
NUCLEUS IS EMULSION NIKFI-BR2.
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