We report the results from measurements of proton polarization P , in the γ +D→p+n reaction at photon energies ranging from 200 to 350 MeV. The data obtained are compared with the measured analysing power A , of the reverse reaction and with model calculations. The assumption of the dominant contribution of isobar configurations in this region is on the whole confirmed by the present proton polarization measurements.
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We report on the first measurement of the single spin analyzing power (A_N) at sqrt(s)=200GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). Data points were measured in the four momentum transfer t range 0.01 < |t| < 0.03 (GeV/c)^2. Our result, averaged over the whole t-interval is about one standard deviation above the calculation, which uses interference between electromagnetic spin-flip amplitude and hadronic non-flip amplitude, the source of A_N. The difference could be explained by an additional contribution of a hadronic spin-flip amplitude to A_N.
The single spin analyzing power for 3 T intervals.
The analyzing powers of π+ and π− were measured using an incident 22−GeV/c transversely polarized proton beam at the Brookhaven Alternating Gradient Synchrotron. A magnetic spectrometer measured π± inclusive asymmetries on a hydrogen and a carbon target. An elastic polarimeter with a CH2 target measured pp elastic-scattering asymmetries to determine the beam polarization using published data for the pp elastic analyzing power. Using the beam polarization determined from the elastic polarimeter and asymmetries from the inclusive spectrometer, analyzing powers AN for π± were determined in the xF and pT ranges (0.45–0.8) and (0.3–1.2 GeV/c), respectively. The analyzing power results are similar in both sign and character to other measurements at 200 and 11.7 GeV/c, confirming the expectation that high-energy pion inclusive analyzing powers remain large and relatively energy independent. This suggests that pion inclusive polarimetry may be a suitable method for measuring future beam polarizations at BNL RHIC or DESY HERA. Analyzing powers of π+ and π− produced on hydrogen and carbon targets are the same. Various models to explain inclusive analyzing powers are also discussed.
Analyzing power measurements for PI+ and PI- production on the carbon target at incident momentum 21.6 GeV. See text of article for definitions of method 'A' and 'B'.
Analyzing power measurements for inclusive PI- production from the hydrogen target.
Analyzing power measurements for inclusive PI+ production from the hydrogen target.
Polarization measurements in the A(p, 2p)B reactions on 6Li, 7Li, and 28Si nuclei at a proton-beam energy of 1 GeV were performed in a kinematically complete experiment. By using a two-arm magnetic spectrometer, two secondary protons were recorded in coincidence at asymmetric scattering angles of θ1=15°−26° and θ2=58.6° for residual-nucleus momenta in the range K B=0–150 MeV/c. Either arm of the spectrometer was equipped with polarimeters based on proportional chambers. The data coming from this experiment are analyzed within the distorted-wave impulse approximation. It is shown that the polarization of recoil protons formed at angle θ2 in the interaction featuring a proton from the P shell of the 7Li nucleus can be described under the assumption of an effective intranuclear-proton polarization by using the single-particle shell-model wave function of the nucleus. Our data on the polarizations of the two protons from the reaction (p, 2p) on a 28Si nucleus also suggest the effective polarization of the protons in the D shell of the 28Si nucleus. It is found that, for high recoil-nucleus momenta of K B≥90 MeV/c, the effective polarization of the protons in the P shell of the 6Li nucleus—this polarization was discovered in studying the polarization of recoil protons in the reaction 6Li(p, 2p)5He—cannot be described within the shell model assuming LS coupling. As might have been expected, the polarization of recoil protons knocked out from the S shells of the 6Li and 7Li nuclei comply well with the predictions obtained in the impulse approximation with allowance for the depolarization effect alone.
REACTION WITH THE LI6 P-SHELL PROTON.
REACTION WITH THE LI6 P-SHELL PROTON.
REACTION WITH THE LI6 P-SHELL PROTON.
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The tensor analyzing power A yy in inclusive breakup of 9 GeV/c deuterons on carbon has been measured at the detected proton angle of 85 mr. The analyzing power remains positive at the highest measured momentum of the proton in definite contradiction with the predictions of the existing models. The vector analyzing power A y has been obtained simultaneously with A yy .
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A polarized proton beam extracted from SATURNE II was scattered on an unpolarized CH 2 target. The angular distribution of the beam analyzing power A oono was measured at large angles from 1.98 to 2.8 GeV and at 0.80 GeV nominal beam kinetic energy. The same observable was determined at the fixed mean laboratory angle of 13.9° in the same energy range. Both measurements are by-products of an experiment measuring the spin correlation parameter A oon .
Analysing power measurements at a fixed laboratory angle of 13.9 degrees.
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We have mesured the polarization of 375-GeV/c Σ+ and Σ¯ − hyperons produced by 800-GeV/c protons incident on a Cu target. We find that the Σ+ polarization rises with increasing pt to a maximum of 16% at pt=1.0 GeV/c and then decreases to 10% at pt=1.8 GeV/c. We compare this Σ+ polarization with data at lower energies. The Σ¯ − polarization has been measured for the first time. It has the same sign as the Σ+ but smaller magnitude in a similar kinematical region.
Data from Horizontal targeting.
Data from Vertical targeting.
Data from Horizontal targeting.
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Proton momentum in deuteron rest frame (ANTILAB).
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