The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.
We present the xF and pT differential cross sections of J/ψ and ψ′, respectively, in the ranges −0.05<xF<0.25 and pT<3.5 GeV/c. The data samples are constituted by about 12 000 J/ψ and 200 ψ′ produced in proton-silicon interactions at 800 GeV/c and decaying into opposite sign muons. The xF and pT distributions are compared with recent results from experiments E789 at the same energy and to leading order QCD predictions using the MRS D0 parametrization for the parton structure function. The measured shapes of the differential cross sections, except for the dσ/dxF at small xF, agree very well with the prediction, even though their value is quite a bit larger than the prediction. We also present the cosθ differential cross section of the J/ψ which indicates unpolarized production in contrast with color octet models predictions.
Fermilab experiment E735 located at the CO intersection region of the\(\sqrt s= 1.8\) TeV\(p\bar p\) collider analysed over 900 Φ→K+K− events. Measured were the transverse momentum spectrum, the correlation between the average transverse momentum <pt> and the charged particle multiphcityNc, as well as the probability of Φ production per charged track,NΦ/Nc, versusNc. We have also made an estinate of the total inclusive cross section for Φ mesons,\(\sigma (p\bar p \to \phi X) = 7.3 \pm 2.2 mb\).
We present the results of a search for the production of light elements in p¯p collisions at the Fermilab Tevatron collider. Momentum, time of flight, and dE/dx measurements are used to distinguish nuclei from elementary particles. A production ratio for deuterium to hydrogen is calculated and compared to the primordial value of the big bang model. Some evidence for tritium is found and none for helium isotopes.
Inclusive single-particle spectra for π± production are presented for data from π±p interactions at 100 GeV/c. The spectra for the four reactions π±p→π±+anything are compared as a function of laboratory longitudinal momentum, Feynman x, center-of-mass (c.m.) rapidity, and transverse momentum squared. Comparisons are also made between these data and analogous data from 16 and 18.5 GeV/c π±p interactions and the energy dependence is discussed. Average values of the transverse momentum are given as a function of the longitudinal momentum and charged-particle multiplicity. A comparison of the charge distributions is presented as a function of rapidity and c.m. energy.
The invariant cross section for production of jet pairs in 400-GeV/c pp interactions has been measured as a function of pT in the pT range 4 to 9 GeV/c. The results are in good agreement with predictions of perturbative QCD models.
The dijet invariant mass distribution has been measured in the region between 120 and 1000 GeV/c2, in 1.8-TeV pp¯ collisions. The data sample was collected with the Collider Detector at Fermilab (CDF). Data are compared to leading order (LO) and next-to-leading order (NLO) QCD calculations using two different clustering cone radii R in the jet definition. A quantitative test shows good agreement of data with the LO and NLO QCD predictions for a cone of R=1. The test using a cone of R=0.7 shows less agreement. The NLO calculation shows an improvement compared to LO in reproducing the shape of the spectrum for both radii, and approximately predicts the cone size dependence of the cross section.
We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV p¯p collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval |η|<0.7. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region 120<MA<210 GeV for axigluon width ΓA=NαsMA6, with N=5.
Inclusive jet production at s=1.8 TeV has been measured in the CDF detector at the Fermilab Tevatron p¯p Collider. Jets with transverse energies (Et) up to 250 GeV have been observed. The Et dependence of the inclusive jet cross section is consistent with leading-order quantum-chromodynamic calculations, and comparison with lower-energy data shows deviations from scaling consistent with QCD. A lower limit of 700 GeV (95% confidence level) is placed on the quark compositeness scale parameter Λc associated with an effective contact interaction.
Results are presented from analyses of jet data produced in pbarp collisions at sqrt{s} = 630 and 1800 GeV collected with the DO detector during the 1994-95 Fermilab Tevatron Collider run. We discuss details of detector calibration, and jet selection criteria in measurements of various jet production cross sections at sqrt{s} = 630 and 1800 GeV. The inclusive jet cross sections, the dijet mass spectrum, the dijet angular distributions, and the ratio of inclusive jet cross sections at sqrt{s} = 630 and 1800 GeV are compared to next-to-leading-order QCD predictions. The order alpha_s^3 calculations are in good agreement with the data. We also use the data at sqrt{s} = 1800 GeV to rule out models of quark compositeness with a contact interaction scale less than 2.2 TeV at the 95% confidence level.
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