Macroscopic Strings and "Quirks" at Colliders

TL;DR

This paper explores the theoretical implications and collider signatures of quirks, hypothetical particles connected by long, stable strings, which could produce distinctive signals at high-energy colliders depending on the string scale.

Contribution

It introduces a detailed analysis of quirk phenomenology across different string length scales and predicts unique collider event signatures for each regime.

Findings

Macroscopic strings produce separated quirk tracks with measurable curvature.

Mesoscopic strings result in bound states with variable invariant mass.

Microscopic strings lead to prompt annihilation and hadronic fireball events.

Abstract

We consider extensions of the standard model containing additional heavy particles ("quirks") charged under a new unbroken non-abelian gauge group as well as the standard model. We assume that the quirk mass m is in the phenomenologically interesting range 100 GeV--TeV, and that the new gauge group gets strong at a scale Lambda < m. In this case breaking of strings is exponentially suppressed, and quirk production results in strings that are long compared to 1/Lambda. The existence of these long stable strings leads to highly exotic events at colliders. For 100 eV < Lambda < keV the strings are macroscopic, giving rise to events with two separated quirk tracks with measurable curvature toward each other due to the string interaction. For keV < Lambda < MeV the typical strings are mesoscopic: too small to resolve in the detector, but large compared to atomic scales. In this case, the bound state appears as a single particle, but its mass is the invariant mass of a quirk pair, which has an event-by-event distribution. For MeV < Lambda < m the strings are microscopic, and the quirks annihilate promptly within the detector. For colored quirks, this can lead to hadronic fireball events with 10^3 hadrons with energy of order GeV emitted in conjunction with hard decay products from the final annihilation.