Antiproton-proton elastic scattering was measured at c.m.s. energies √s =546 and 1800 GeV in the range of four-momentum transfer squared 0.025<-t<0.29 GeV2. The data are well described by the exponential form ebt with a slope b=15.28±0.58 (16.98±0.25) GeV−2 at √s =546 (1800) GeV. The elastic scattering cross sections are, respectively, σel=12.87±0.30 and 19.70±0.85 mb.
Final results (systematic errors included).
Final results (systematic errors included).
Statistical errors only. Data supplied by S. Belforte.
We present a search for electroweak production of single top quarks in $\approx 90$ $pb^{-1}$ of data collected with the DZero detector at the Fermilab Tevatron collider. Using arrays of neural networks to separate signals from backgrounds, we set upper limits on the cross sections of 17 pb for the s-channel process $p\bar{p} \to tb + X$, and 22 pb for the t-channel process $p\bar{p} \to tqb + X$, both at the 95% confidence level.
No description provided.
The antiproton-proton small-angle elastic-scattering distribution was measured at\(\sqrt s \) GeV at the Fermilab Tevatron Collider. A fit to the nuclear-scattering distribution in the range 0.065≤|t|≤0.21 (GeV/c)2 givesb=(16.2±0.5±0.5) (GeV/c)−2 for the logarithmic slope parameter. Using the optical theorem and the luminosity from Collider parameters, we obtain σtoto(1+ρ2)1/2 =(61.7±3.7±4.4)mb.
No description provided.
Cross sections derived assuming RE(AMP)/IM(AMP) = 0.140, see Phys. Lett. B188, 143 (1987).
Slope was derived in the t range -0.065 < t < -0.21 (GeV/c)**2.
We have studied proton-antiproton elastic scattering at s=1800 GeV at the Fermilab Collider, in the range 0.02<|t|<0.13 (GeV/c)2. Fitting the distribution by exp(−B|t|), we obtain a value of B of 17.2±1.3 (GeV/c)−2.
No description provided.
Error contains estimate of systematic effects.
We have measured $\rho$ , the ratio of the real to the imaginary part of the $p \bar{p}$ forward elastic scattering amplitude, at $\sqrt{s}$ = 1.8 TeV. Our result is $\rho$ = 0.132 $\pm$ 0.056; this can be combined with a previous measurement at the same energy to give $\rho$ = 0.135 $\pm$ 0.044.
Measured value of the total cross section.
The measured value of the ratio of real to imaginary part of the forward scattering amplitude.
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.
Results of least square's fit to the distribution.
Total cross section from fit to data.
The dijet angular distribution is measured in the Collider Detector at Fermilab. This measurement covers higher mass ranges and larger scattering angles than previously possible. Good agreement is observed between the data and both leading-order [O(αs2)] and next-to-leading order [O(αs3)] QCD calculations. A limit on quark compositeness of Λc>1.0 TeV is obtained.
No description provided.
No description provided.
No description provided.
We have measured the antiproton-proton total cross section at √s =1.8 TeV at the Fermilab Tevatron Collider; the value obtained is 78.3±5.9 mb. B, the nuclear slope parameter for elastic scattering, was measured to be 16.3±0.5 (GeV/c)−2. From these data, we derive a value for the total elastic cross section.
Nuclear Store Parameter.
Total cross section measurement. Errors contain systematic effects folded including a 15 PCT error in luminosity measurement which dominates the error.
Total cross section assuming RHO = 0.145 (low energy fit). If RHO is taken as 0.24 obtained by UA4 at sqrt(s) = 546 GeV, the value of SIG is reduced by 1.8 PCT.
The differential cross section for elastic antiproton—proton scattering at s =1.8 TeV has been measured over the t range 0.034⩽| t |⩽0.65 (GeV/ c ) 2 . A logarithmic slope parameter, B , of 16.3±0.3 (GeV/ c ) −2 is obtained. In contrast to lower energy experiments, no change in slope is observed over this t range.
Numerical values from FERMILAB-FN-562 suppliedto us by R. Rubinstein. Statistical errors only. t values at centre of each bin.
Nuclear slope parameter. Error contains 0.3 GeV**-2 systematic uncertainty folded.
The DO collaboration reports on a search for the Standard Model top quark in pbar-p collisions at Sqrt(s)=1.8TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50pb-1. We have searched for t-tbar production in the dilepton and single-lepton decay channels, with and without tagging of b-quark jets. We observed 17 events with an expected background of 3.8+/-0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2.0E-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199~+19_21 (stat.)+/- 22 (syst.)GeV/c**2 and its production cross section to be 6.4 +/- 2.2 pb.
Cross section refers to top quark mass equal 199. (+19, -21, +- 22) GeV.
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