Polarization at Small Angles in Anti-proton - Carbon Elastic Scattering at {LEAR} Energies

The SING collaboration Martin, A. ; Birsa, R. ; Bos, K. ; et al.
Nucl.Phys.A 487 (1988) 563-590, 1988.
Inspire Record 261245 DOI 10.17182/hepdata.37001

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 A p C 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 A p C 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 A p C as a c q , we get a c = +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.

6 data tables match query

THETA1(RF=LAB)=8 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.

THETA1(RF=LAB)=5 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.

THETA1(RF=LAB)=8 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.

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CROSS-SECTION ASYMMETRY OF THE gamma n ---> pi- p REACTION BY POLARIZED PHOTONS IN THE THIRD AND FOURTH RESONANCE REGIONS

Adamian, F.V. ; Akopian, G.G. ; Galumian, P.I. ; et al.
EFI-722-37-84-YEREVAN, 1984.
Inspire Record 206944 DOI 10.17182/hepdata.18433

None

5 data tables match query

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Measurement of the neutral weak form factors of the proton.

The HAPPEX collaboration Aniol, K.A. ; Armstrong, D.S. ; Baylac, M. ; et al.
Phys.Rev.Lett. 82 (1999) 1096-1100, 1999.
Inspire Record 478059 DOI 10.17182/hepdata.31319

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G_E^s. The result, A=-14.5 +- 2.2 ppm, is consistent with the electroweak Standard Model and no additional contributions from strange quarks. In particular, the measurement implies G_E^s + 0.39G_M^s = 0.023 +- 0.034 (stat) +- 0.022 (syst) +- 0.026 (delta G_E^n), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor.

1 data table match query

Longitudinally polarized beam. C=L and C=R means left- and right polarization. The second systematic uncertainty arises from the estimated uncertainty inthe neutron electromagnetic from factor.