Search for New Particles Decaying to b bbar in p pbar Collisions at sqrt{s}=1.8 TeV

We have used 87 pb^-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to b bbar. We present model-independent upper limits on the cross section for narrow resonances which excludes the color-octet technirho in the mass interval 350 < M < 440 GeV/c^2. In addition, we exclude topgluons, predicted in models of topcolor-assisted technicolor, of width Gamma = 0.3 M in the mass range 280 < M < 670 GeV/c^2, of width Gamma = 0.5 M in the mass range 340 < M < 640 GeV/c^2, and of width Gamma = 0.7 M in the mass range 375 < M < 560 GeV/c^2.Comment: 17 pages in a LaTex generated postscript file, with one table and four figures. Resubmitted to Physical Review Letters. Minor clarifications were added to the text. The displayed normalization of the resonance models in Figure 2 was modified to correspond to our 95% CL upper limit on the cross section (instead of arbitrary normalization which was used previously). All results are identical to those in the previous submissio

Test of the External Muon Identifier Efficiency

We wish to measure the EMI efficiency at hadron momenta higher than the 3 GeV used at the Beavatron. We propose to use the 30 M{sup 3} bubble chamber as the momentum and spatial analyzer of charged hadrons both of the incident beam and those final state hadrons of interactions that occur within the chamber. We would use the EMI modules as mounted on the bubble chamber vacuum tank to measure the efficiency of the EMI absorbers (coils and zinc) over a wide range of momenta. A hadron signature would be either the lack of a proportional chamber (pc) encoding within the '96% muon-circle' or a multiple PC encoding. We shall attempt to identify {pi}-{mu} decays in the chamber to use as a source of muons. Such a test would give us experience in spatially reconstructing tracks within the chamber and in projecting their trajectories out to the EMI detector modules. The early portion of this test could utilize whatever hadron beam the NAL bubble chamber group would be using at the time. We would make a copy of an adequate number of the original frames and compare the film quality with the original ones to test whether the EMI experiments of any sort, neutrinos or hadrons, could use copies rather than the original film negatives. The later portions of the test may require incident beams of momenta and particles of our choosing. Approximately 10{sup 4} interactions would be needed for the early test