S. E. Kuhlmann

Observation of the B{sub_c} Meson in p{ovr p} collisions at {radical}{ovr s} = 1.8 TeV.

We have observed bottom-charm mesons B_c via the decay mode Bc ->J/psi lepton neutrino in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi + lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B_c mass to be 6.40 +- 0.39 +- 0.13 GeVc^2 and the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We measured the production cross section times branching ratio for B_c ->J/psi lepton neutrino relative to that for B+ ->J/psi K to be 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime).

Search for long-lived parents of Z{sup 0} bosons in p{ovr p} collisions at {radical}{ovr s} = 1.8 TeV.

We search for new long-lived particles which decay to Z{sup 0} bosons by looking for Z{sup 0}{yields}e{sup +}e{sup -} decays with displaced vertices. We find no evidence for parent particles of the Z{sup 0} with long lifetimes in 90 pb{sup -1} of data from the CDF experiment at Fermilab. We set a cross section limit as a function of the lifetime of the parent particle for both a generic Z{sup 0} parent and a fourth-generation, charge -1/3 quark that decays into Z{sup 0}b.