L. G. Ratner

Energy dependence of spin-spin forces in 90°cm elastic p-p scattering

Abstract 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 .

Simultaneous Measurement of 2 and 3 Spins in Proton Proton Elastic Scattering at 6-GeV/c

Abstract 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.

Measurement of Proton Proton Elastic Scattering in Pure Initial Spin States at 11.75-GeV/c

Abstract The elastic cross section for proton proton scattering at 11.75 GeV/c was measured at the Argonne ZGS using a 50% polarized target. In the range p⊥2=0.6 → 2.2 (GeV/c)2 we obtained precise measurements of d σ d t(ij) for the ⇈ ⇊, and ⇅ initial spin states perpendicular to the scattering plane. We confirmed that the asymmetry parameter, A, decreases with energy in the diffraction peak, but is approximately energy-independent at large p⊥2. We found that the spin correlation parameter cnn acquires rather dramatic structure, and at large p⊥2 seems to grow with energy.

Spin Dependence of PP Inclusive Reactions

Data are presented for the spin correlation parameter ANN in the inclusive reactions P↑ + P↑ → π+ + X and P↑ + P↑ → P + X at 6 GeV/c. For π+ inclusives substantial asymmetries are observed which decrease with increasing momentum transfer squared P T 2 . For proton inclusives ANN is small but appears to increase with increasing P T 2 .

Measurement of A and A/sub nn/ in p + p. -->. p + p at 6 GeV/c

Previous measurements of the 6 GeV/c p - p elastic scattering rates have been extended with beam and target polarizations normal to the scattering plane. Improvements to the measuring technique include additional momentum resolution added to the recoil arm and increased solid angle resulting from two-element hodoscopes. Beam intensity was increased by a factor of 3 and additional shielding was installed. Along with the usual statistical uncertainty and errors in measurement of the target polarization, a term was added in quadrature due to a systematic difference between target and beam asymmetries (A/sub T/ and A/sub B/). (GHT)

Energy dependence of spin‐spin effects in p−p elastic scattering at 90°CM

Data are presented on the energy dependence of the spin-spin correlation parameter, Ann, for pp elastic scattering at 90°cm over the beam momentum range 6 to 12. 75 GeV/c. Ann is about 10% up to 8 GeV/c then climbs rapidly to a value of about 60% at 11 GeV/c. Our data indicate that Ann may depend only on the variable P ⊥ 2 and suggests that Ann may reach a limiting value of about 60%.