Search for Long-Lived Parents of Z Bosons in pbar-p Collisions at sqrt{s}=1.8 TeV

TL;DR

This study searches for long-lived particles decaying into Z bosons using displaced vertex detection in proton-antiproton collisions, setting limits on their production cross sections and lifetimes.

Contribution

It introduces a search method for long-lived parents of Z bosons and provides new cross section limits based on Fermilab data.

Findings

No evidence for long-lived Z parents was observed.

Set upper limits on production cross sections as a function of lifetime.

Constraints on fourth-generation quark models were established.

Abstract

We search for new long-lived particles which decay to Z bosons by looking for Z->e+e- decays with displaced vertices. We find no evidence for parent particles of the Z with long lifetimes in 90 pb-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 parent and a fourth-generation, charge -1/3 quark that decays into Z+b.