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Polarization at small angles in antiproton-carbon elastic scattering at lear energies

1988; Elsevier BV; Volume: 487; Issue: 3-4 Linguagem: Inglês

10.1016/0375-9474(88)90028-0

1873-1554

A. Martin, R. Birsa, K. Bos, F. Bradamante, D.V. Bugg, S. Dalla Torre-Colautti, J. R. Hall, E. Heer, R. Heß, J.C. Kluyver, R. Kunne, C. Lechanoine-Leluc, A. Penzo, D. Rapin, P. Schiavon, F. Tessarotto, A. Villari, A. Zanetti,

Muon and positron interactions and applications

A double-scattering experiment of antiprotons on carbon has been carried out at the Low-Energy Antiproton Ring (LEAR) at CERN, to measure the polarization parameter ApC in antiproton-carbon elastic scattering at small angles. The polarization parameter has been inferred from the azimuthal distribution of the antiprotons after the second scattering. Data have also been collected with a liquid-hydrogen target as the second scatterer, thus allowing the sign of ApC to be determined. The experiment has been performed at two momenta of the extracted antiproton beam, 800 and 1100 MeV/c. A small positive value of the polarization has been observed, compatible with energy independence and a linear increase with the momentum transfer q. Parametrizing ApC as acq, we get ac = +0.72 0.10+0.09(GeV/c)−1. This result is compared with potential model predictions for N̄N amplitudes through a Glauber theory calculation.