The energy dependence of the pp elastic analyzing power has been measured using an internal target during polarized beam acceleration. The data were obtained in incident-energy steps varying from 4 to 17 MeV over an energy range from 0.5 to 2.0 GeV. The statistical uncertainty of the analyzing power is typically less than 0.01. A narrow structure is observed around 2.17 GeV in the two-proton invariant mass distribution. A possible explanation for the structure with narrow resonances is discussed.
Statistical errors only.
We measured d σ d t(90° cm ) for ↑+ p ↑→ p + p from 1.75 to 5.5 GeV/ c , using the Argonne zero-gradient synchrotron 70% polarized proton beam and a 70% polarized proton target. We found that the spin-spin correlation parameter. A nn , equals 60% at low energy, then drops sharply to about 10% near 3.5 GeV/ c , and remains constant up to 5.5 GeV/ c .
ANALYZING POWER. QUOTED ERRORS DUE TO 4.3 PCT POINT TO POINT RELATIVE ERROR.
THE SPIN-SPIN CORRELATION PARAMETER CNN IS NOW DENOTED BY ANN ACCORDING TO THE NEW ANN ARBOR CONVENTION.
Recent data are presented on spin-spin correlation parameters CLL=(L,L;0,0) and CSL=(S,L;0,0) at forward angles from 1.18 to 2.47 GeV/c incident momenta in proton-proton elastic scattering. Values for ΔσL (inelastic) are derived and are shown to disagree with predictions of theoretical models attempting to describe p−p scattering without dibaryon resonances. Finally, the CLL and CSL data discriminate among various phase-shift solutions, and will lead to a clarification of the p−p phase shifts.
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We have measured π±p and pp elastic differential cross sections in the range |cosθc.m.|<0.35 for incident momenta from 2 to 9.7 GeV/c for π−p and pp and from 2 to 6.3 GeV/c for π+p. We find that the fixed-c.m.-angle πp differential cross sections cannot be described as simple functions of s. The data are compared to the energy and angular dependence predicted by the constituent model of Gunion, Brodsky, and Blankenbecler.
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Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta pp (energies Tp) from 1100 to 3300MeV/c (500 to 2500 MeV) in the angular range 35°≤Θc.m.≤90° with a detector providing ΔΘc.m.≈1.4° resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH2 fiber target, taking particular care to monitor luminosity as a function of Tp. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found.
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