[en] CDF has searched for 2nd generation leptoquarks, new gauge bosons W' and Z', axigluons, excited quarks, color octet technirhos and E₆ diquarks. We place the most stringent limits on direct production of these exotic particles

[en] A study was made of three separate diffractive dissociation channels in π^-d interactions at 15 GeV/c incident momentum. Data were compared for the dissociation of a pion into 3π and 5π, and the dissociation of a neutron into pπ^-. Low mass diffractive enhancements are seen in all three channels. In the 3πd channel, evidence is presented for a third 3π enhancement at 1.92 GeV, which is associated with gπ final states. This continues the pattern of pπ and fπ states in the A₁ and A₃ enhancements. Evidence is also presented for an enhancement in the dπ⁺π^- spectrum which may be explainable as an extension of the d* mechanism to Nππ states. In the 5πd channel, a 5π enhancement is seen at approximately 2 GeV, but with no significant two body final states. The neutron dissociation channel shows evidence of two separate components in the pπ^- spectrum--a low mass diffractive enhancement at 1.25 GeV, and two N* peaks which appear to be resonances. Comparison with ISR data suggests that the N* resonances are also produced by Pomeron exchange

[en] We present three searches for new particles at CDF. First, using 70 pb^-1 of data we search the dijet mass spectrum for resonances. There is an upward fluctuation near 550 GeV/c² (2.6σ) with an angular distribution that is adequately described by either QCD alone or QCD plus 5% signal. There is insufficient evidence to claim a signal, but we set the most stringent mass limits on the hadronic decays of axigluons, excited quarks, technirhos, W', Z', and E6 diquarks. Second, using 19 pb^-1 of data we search the b-tagged dijet mass spectrum for b bar b resonances. Again, an upward fluctuation near 600 GeV/c² (2σ) is not significant enough to claim a signal, so we set the first mass limits on topcolor bosons. Finally, using 67 pb^-1 of data we search the top quark sample for t bar t resonances like a topcolor Z'. Other than an insignificant shoulder of 6 events on a background of 2.4 in the mass region 475--550 GeV/c², there is no evidence for new particle production. Mass limits, currently in progress, should be sensitive to a topcolor Z' near 600 GeV/c². In all three searches there is insufficient evidence to claim new particle production, yet there is an exciting possibility that the upward fluctuations are the first signs of new physics beyond the standard model

[en] We report on preliminary measurements of direct photons in bar pp collisions at √s = 1.8 TeV from the 1988--89 run of the Collider Detector at Fermilab (CDF). The inclusive direct photon cross section, measured for photon transverse momentum in the range 13 < P_t < 68 GeV, has an excess at low P_t compared to recent Quantum Chromodynamic (QCD) calculations. The pseudorapidity distribution of the away-side jet, for events with 27 < P_t < 33 GeV, agrees with QCD predictions. Measurements of the K_t kick in photon-jet events are also presented. 8 refs., 10 figs., 1 tab

[en] We present a measurement of the cross section for production of two isolated prompt photons in p bar p collisions at √s = 1.8 TeV. The cross section, measured as a function of transverse momentum (PT) of each photon, is roughly three times what full QCD calculations predict. Calculations that only include the Born and box diagrams, which are commonly used to estimate the prompt diphoton background to Higgs decay at future hadron colliders, are lower than our measurement by roughly ii factor of five. We also study variables sensitive to K_T: the transverse momentum of initial state partons. The vector sum of the transverse momenta of both photons, K_T = |rvec P_T1 + rvec P_T2|, is compared to previous measurements at lower collision energies, and we find a roughly logarithmic increase with √s. The measured mean value is < K_T >= 5.1 ± 1.1 GeV at √s = 1.8 TeV

[en] In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to b anti b at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 0.77-0.95 TeV for Run II (2 fb^-1) and 1.0 - 1.2 TeV for TeV33 (30 fb^-1)

[en] If quarks are composite particles then excited states are expected. We estimate the discovery mass reach as a function of integrated luminosity for excited quarks decaying to dijets at the Tevatron the mass reach is 0.94 TeV for Run 11 (2 fb^-1) and 1. 1 TeV for TeV33 (30 fb^-1). At the LHC the mass reach is 6.3 TeV for 100 fb^-1. At a VLHC with a center of mass energy √s, of 50 TeV (200 TeV) the mass reach is 25 TeV (78 TeV) for an integrated luminosity of 10⁴ fb^-1. However, an excited quark with a mass of 25 TeV would be discovered at a hadron collider with √s = 100 TeV and an integrated luminosity of 13 fb^-1, illustrating a physics example where a factor of 2 in machine energy is worth a factor of 1000 in luminosity

[en] We present measurements of isolated prompt photon production in bar pp collisions at √s = 1.8 TeV from the Fermilab experiments CDF and D0. Precision measurements of prompt photon production from CDF constrain the gluon distribution of the proton, and recent results from D0 agree with CDF and QCD. The pseudorapidity distribution of the jet in photon events at CDF is used to constrain parton distributions. Gauge boson (g,γ,W) + jet angular distributions at CDF show good agreement with QCD and illustrate the spin of quarks and gluons. Diphoton candidate mass distributions from CDF are used to search for new physics and measure the background to Higgs→γγ. Finally, CDF searches for resonances in the W+jet and -γ+jet mass distributions, and thereby excludes excited states of composite quarks for mass M* < 540 GeV/c² at 95% confidence level

[en] We present a preliminary search for new particles decaying to dijets using CDF data from the 1992--1993 run. We set the highest mass limits on axigluons and excited quarks, and the first mass limit on a color octet technirho

[en] In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to t anti t at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 1.0 - 1.1 TeV for Run H (2 fb^-1) and 1.3 - 1.4 TeV for TeV33 (30 fb^-1)