Search for Long-Lived Parents of the Z Boson

TL;DR

This paper reports a search for long-lived particles decaying into Z bosons, setting limits on models predicting such particles, but finds no evidence of their existence.

Contribution

It introduces a novel search method for long-lived particles decaying into Z bosons and provides new cross-section limits on a fourth generation quark model.

Findings

No evidence of long-lived parent particles was observed.

Cross-section limits were established for the fourth generation quark model.

The study enhances constraints on models predicting long-lived particles decaying to Z bosons.

Abstract

We present the results of a search for new particles with long lifetime that decay to a Z boson. A long-lived parent of the Z is predicted by several models in addition to being an experimentally clean channel. We vertex dimuons with invariant mass near the Z peak and study the decay length distribution. No evidence of a long-lived component is found, and cross-section limits are presented on a fourth generation quark model.