Measurement of the analyzing power A N in pp elastic scattering in the CNI region with a polarized atomic hydrogen gas jet target
/ Authors
H. Okada, I. Alekseev, A. Bravar, G. Bunce, S. Dhawan, R. Gill, W. Haeberli, O. Jinnouchi, A. Khodinov, A. Kponou
and 9 more authors
Y. Makdisi, W. Meng, A. Nass, N. Saito, H. Spinka, E. Stephenson, D. Svirida, T. Wise, A. Zelenski
/ Abstract
Abstract A precise measurement of the analyzing power A N in proton–proton elastic scattering in the region of 4-momentum transfer squared 0.001 | t | 0.032 ( GeV / c ) 2 has been performed using a polarized atomic hydrogen gas jet target and the 100 GeV/ c RHIC proton beam. The interference of the electromagnetic spin-flip amplitude with a hadronic spin-nonflip amplitude is predicted to generate a significant A N of 4–5%, peaking at − t ≃ 0.003 ( GeV / c ) 2 . This kinematic region is known as the Coulomb nuclear interference region. A possible hadronic spin-flip amplitude modifies this calculable prediction. We present the first precise result of the CNI asymmetry and shape as a function of t . Our data are well described by the CNI prediction with the electromagnetic spin-flip alone and do not support the presence of a large hadronic spin-flip amplitude.
Journal: Physics Letters B