The invariant double-differential cross section, E 1 E 2 d 6 σ / d p 3 1 d p 3 2 , and the double-spin asymmetry, A LL , for inclusive multi-γ pair production in which γ-rays came from neutral mesons were measured with a 200 GeV / c longitudinally-polarized proton beam and a longitudinally-polarized proton target. Most of the multi-γ pairs comes from two-jet type events which are sensitive to partonic interaction. The A LL values were found to be consistent with zero. The invariant double-differential cross section for inclusive π 0 π 0 production was also measured. These measured cross sections are consistent with LUND Monte Carlo simulations. Using the LUND Monte Carlo simulation package with the Carlitz-Kaur model of spin dependent distribution functions of valence quarks, the A LL values have been compared with theoretical predictions of gluon polarization, ΔG / G . The results put restrictions on the size of ΔG / G in the region of 0.05 ⪅ x ⪅ 0.35.
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We present a total of 191 and 203 data points of the elastic neutron-protonspin correlation parameters A ookk and A oosk , respectively. Both observables were measured in a large angular interval. The observable A ookk was measured from 0.312 to 1.10 GeV and A oosk from 0.80 to 1.10 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the polarized Saclay frozen-spin proton target. The beam polarization was oriented either along the beam direction or sideways, the target polarization was oriented longitudinally. Data are compared with phase-shift analyses predictions and with the PSI, LAMPF and SATURNE II results. Present results provide an important contribution to any future theoretical or phenomenological analysis.
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We present results of the total cross section differenceΔσТ obtained in transmission measurements at the energies 0.86, 0.88, 0.91 and 0.94 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was transmitted through the polarized Saclay frozen-spin proton target. The beam and target polarizations were oriented in the vertical direction. The present results agree with previous SATURNE measurements and improve the amplitude analysis in the forward direction.
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Average of this result and data from Fontaine et al. 1991, Nucl.Phys. B358, 297 (<a href=http://durpdg.dur.ac.uk/scripts/reacsearch.csh/TESTREAC/red+2233> RED = 2233 </a>).
The depolarization parameter D 0 n 0 n in the charge-exchange reaction p p ↑→ n n ↑ has been measured for the first time at the CERN Low Energy Antiproton Ring (LEAR) at 875 MeV/ c antiproton beam momentum, in the forward hemisphere. The measured values of D 0 n 0 n are always smaller than ±0.3, indicating that the two-spin amplitudes dominate the scattering matrix as suggested by the meson exchange potential models.
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We present a total of 323 data points of the spin correlation parameter A oonn (np) in a large angular interval at eight energies between 0.8 and 1.1 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the polarized Saclay frozen-spin proton target. The present data are the first existing results above 0.8 GeV.
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Results are presented for the spin-spin correlation parameters CSS and CLS for free np elastic scattering at neutron beam kinetic energies of 484, 634, 720, and 788 MeV and c.m. angles between 25° and 80°. The measurements were performed with a polarized neutron beam and a polarized proton target. These are the first measurements of this type to be reported in the forward angular region with a free polarized neutron beam. The observables CSS and CLS are both small at all energies, except for CLS at 788 MeV, which is larger than phase-shift analysis predictions by more than one standard deviation for most of the measured points.
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Final results are presented for the spin-spin correlation parameters CSL and CLL for np elastic scattering with a polarized neutron beam incident on a polarized proton target. The beam kinetic energies are 484, 634, and 788 MeV, and the c.m. angular range is 80°-180°. These data will contribute significantly to the determination of the isospin-0 amplitudes in the energy range from 500 to 800 MeV.
Pure np elastic scattering spin variables. CLL and CSL derived from measured combined spin variable. Thus the errors on CLL and CSL are slightly correlated. There are also additional systematic errors of 7 pct associated with beam and 3.3 pct target polarizations respectively.
Pure np elastic scattering spin variables. CLL and CSL derived from measured combined spin variable. Thus the errors on CLL and CSL are slightly correlated. There are also additional systematic errors of 7 pct associated with beam and 3.3 pct target polarizations respectively.
Pure np elastic scattering spin variables. CLL and CSL derived from measured combined spin variable. Thus the errors on CLL and CSL are slightly correlated. There are also additional systematic errors of 7 pct associated with beam and 3.3 pct target polarizations respectively.
We have measured the spin-transfer parameters KLL, KSL, KLS, and KSS at 635 MeV from 50° to 178° c.m. and at 485 MeV from 74° to 176° c.m. These new data have a significant impact on the phase-shift analyses. There are now sufficient data near these energies to overdetermine the elastic nucleon-nucleon amplitudes.
Spin transfer parameters from np elastic scattering at 635 MeV. There is an additional overall normalisation of 2 PCT.
Spin transfer parameters from np elastic scattering at 485 MeV. There is an additional overall normalisation of 2 PCT.
The two-spin parameter A LL in inclusive π 0 productionby longitudinally-polarized protons and antiprotons on a longitudinally-polarized proton target has been measured at the 200 GeV Fermilab spin physics facility, for π 0 's at x F =0 with 1⩽ p t ⩽3 GeV/ c . The results exclude, at the 95% confidence level, values of A LL (pp) > 0.1 and < − 0.1 for π 0 's produced by protons, and values of A LL ( p p) > 0.1 and < −0.2 for incident antiprotons. The relevance of A LL (pp) for the gluon spin density is discussed. The data are in good agreement with “conventional”, small or zero, gluon polarization.
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Final results for total cross section differences Δσ T and Δσ L measured with a polarized neutron beam transmitted through a polarized proton target are presented. Measurements were carried out at SATURNE II, at 11 energies between 0.63 and 1.1 GeV for Δσ T and at 9 energies between 0.312 and 1.1 GeV for Δσ L . The results are compared with measurements at PSI and LAMPF as well as with Δσ L data points deduced from p-d and p-p transmission experiments at the ANL-ZGS. The present results together with the corresponding pp data allow to determine two of the three imaginary parts of forward scattering amplitudes for isospin I = 0.
Measurements of the tranverse cross section differences.
Measurements of the tranverse cross section differences.
Measurement of the longitudinal cross section difference.
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