We have measured ρ0, ω (combined) and ϕ electroproduction over a range of virtual-photon four-momentum Q2 from 0.4 to 2.2 GeV2 and for photon energies ν from 2.7 to 8.6 GeV. We find that the slope of the t (momentum transfer) dependence of the ρ0 and ω forward peak decreases with increasing Q2 to less than half of the photoproduction slope.
The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.
Cross sections for inelastic scattering of electrons from hydrogen and deuterium were measured for incident energies from 4.5 to 18 GeV, at scattering angles of 18°, 26°, and 34°, and covering a range of squared four-momentum transfers up to 20 (GeVc)2. Neutron cross sections were extracted from the deuterium data using an impulse approximation. Comparisons with the proton measurements show significant differences between the neutron and proton cross sections.
Axis error includes +- 1/1 contribution (DUE TO ERRORS IN ABOVE CORRECTIONSFOR DEAD-TIME LOSSES, INEFFICIENCIES IN E- IDENTIFICATION).
We report on an experiment to obtain differential cross sections for K+p elastic scattering in the vicinity of the possible exotic baryon, the Z1*(1900). The differential cross sections are based on typically 70 000 selected events in the angular region −0.9≤cosθc.m.≤0.9 at each of 22 momenta from 0.865 to 2.125 GeV/c. The data are intended for use in partial-wave analysis to search for the Z1*.
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We have measured ep, eπ+, and eπ− coincidences for scattered electrons in the range Q2=0.4 to 2.2 GeV2 and W=2 to 4 GeV. We find (a) that vector-meson production decreases with Q2 more rapidly than does the total virtual-photon-plus-proton cross section, more rapidly even than the prediction of simple vector dominance, (b) that the slope of the t distribution in ρ and ω production becomes flatter with increasing Q2 and seems to be at least approximately a function of the single variable xρ=(Q2+mρ2)2Mν, (c) that the fraction of final states containing a proton decreases with increasing Q2, (d) that in the central region of longitudinal momenta the inclusive π+ yield seems to increase relative to the π− yield as Q2 increases, and (e) that the average transverse momentum of π− is greater than of π+ in the central region of longitudinal momenta.
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The data with (C=Q=RHO+OMEGA) are obtained by excluding the contribution from RHO and OMEGA production.
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An experiment was done using an accelerated polarized proton beam and a polarized proton target. The elastic cross section for proton-proton scattering at 6.0 GeV/c and P⊥2=0.5−1.6 (GeV/c)2 was measured in the spin states ↑ ↑, ↓ ↓, and ↑ ↓ perpendicular to the scattering plane. The cross sections were found to be unequal by up to a factor of 2.
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We report measurements of the ratio of the deep-inelastic electron-neutron to electron-proton differential cross sections in the threshold ( ω <3) region. The ratio was found to scale and to decrease monotically with decreasing ω . No violation of the quark model lower bound of 0.25 was observed in the ratio.
DATA ARE AVERAGED THROUG AVAILABLE KINEMATIC REGION.
The elastic cross section for proton proton scattering at 6 GeV c was measured using a 70% polarized beam and a 75% polarized target at the Argonne ZGS. In the range P ⊥ 2 = 0.5 → 2.0( GeV c ) 2 we obtained small error measurements for the ↑↑, ↓↓ and ↑↓ initial spin states perpendicular to the scattering plane. At P ⊥ 2 = 0.5 we also measured the recoil spin and found that the 5 different cross sections were very unequal.
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Differential cross sections for the reactions γp→π0p, π+n and γn→π−p, π0n were measured in a single experiment using tagged photons in the energy region 240-450 MeV incident on H21 and H22 targets. Results of the measurements of the ratios π0nπ0p and π−pπ+n are presented. The ratio of isotensor to isovector amplitude is found to be 0.00±0.02.
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Differential cross sections for π+p elastic scattering in the momentum region 1.2 to 2.3 GeV/c are presented for the center-of-mass angular range 0.9>cosθ>−0.9. Typically, 50 000 events were obtained at each of 16 momenta using magnetostrictive-readout wire spark chambers to detect the particles scattered from a liquid hydrogen target. The results are compared to those of the CERN-71 phase-shift analysis. The well-known dips at t≅−0.7 (GeV/c)2 and at u′=−0.2 (GeV/c)2 are observed. In addition, structure is seen at constant u′=−1.3 (GeV/c)2. The results of a pion attenuation study in iron are also presented.
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We report here the results from an experiment to obtain differential cross sections for K−p elastic scattering in the laboratory momentum region from 1.4 to 1.9 GeV/c. These data span the region of a bump in the K−p total cross section at an energy of 2.05 GeV. Approximately 20000 elastic events were obtained at each of four momenta with an angular coverage of 0.9≥cosθc.m.≥−0.9. The data are intended to aid in phase-shift analyses of the resonances causing the bump in the total cross section and to study dip structures at constant values of the Mandelstam variables t and u.
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LEGENDRE POLYNOMIAL COEFFICIENTS.
FROM INTEGRATING LEGENDRE POLYNOMIAL FIT TO D(SIG)/DOMEGA. QUOTED ERRORS INCLUDE NORMALIZATION AND FITTING UNCERTAINTIES.
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