Macroscopic Strings and “Quirks” at Colliders

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 Λ < m. In this case breaking of strings is exponentially suppressed, and quirk production results in strings that are long compared to Λ−1. The existence of these long stable strings leads to highly exotic events at colliders. For 100 eV <∼ Λ <∼ 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 <∼ Λ <∼ 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 <∼ Λ <∼ 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 hadrons with energy of order GeV emitted in conjunction with hard decay products from the final annihilation. ar X iv :0 80 5. 46 42 v3 [ he pph ] 2 5 Se p 20 09