Search for New Particles Decaying to Dijets, Bottom Quarks, and Top Quarks at CDF

Abstract

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 (2.6 sigma) 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 anti-b resonances. Again, an upward fluctuation near 600 GeV (2 sigma) 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 anti-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, there is no evidence for new particle production. Mass limits, currently in progress, should be sensitive to a topcolor Z' near 600 GeV. 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.