Measurement of ρ, the ratio of the real to the imaginary part of thep¯pforward elastic-scattering amplitude, at √s=1.8 TeV

We have measured {ρ}, the ratio of the real to the imaginary part of the p{}p forward elastic-scattering amplitude, at {}s =1.8 TeV. Our result, {ρ}=0.140±{}0.069, is compared with extrapolations from lower-energy data based on dispersion relations, and with the UA4 value at {}s =546 GeV.