Measurement of the Differential Cross Section D Sigma/Dt in Elastic P(P)Over-Bar Scattering at Root S=1.96 Tev

We present a measurement of the elastic differential cross section d sigma(p (p) over bar -> p (p) over bar)/dt as a function of the four- momentum-transfer squared t. The data sample corresponds to an integrated luminosity of approximate to 31 nb(-1) collected with the D0 detector using dedicated Tevatron p (p) over bar Collider operating conditions at root s = 1.96 TeV and covers the range 0.26 < vertical bar t vertical bar < 1.2 GeV2. For vertical bar t vertical bar < 0.6 GeV2, d sigma/dt is described by an exponential function of the form Ae(-b vertical bar t vertical bar) with a slope parameter b = 16.86 +/- 0.10(stat) +/- 0.20(syst) GeV-2. A change in slope is observed at vertical bar t vertical bar approximate to 0.6 GeV2, followed by a more gradual vertical bar t vertical bar dependence with increasing values of vertical bar t vertical bar.