Dirac vs Majorana gauginos at a 100 TeV collider

TL;DR

This paper compares the detection prospects of Majorana and Dirac gaugino models at a future 100 TeV collider, highlighting differences in discovery reach, fine-tuning, flavor constraints, and dark matter implications.

Contribution

It provides a detailed analysis of how Majorana and Dirac gaugino models can be distinguished at a 100 TeV collider, including their discovery potential and theoretical constraints.

Findings

Heavy gluino masses reduce squark discovery in Dirac models

Similar reach for squark and gluino masses when they are close

Collider searches can probe dark matter candidates in both models

Abstract

We compare the prospects for observing theories with Majorana or Dirac gauginos at a future 100 TeV proton-proton collider. Calculating the expected discovery and exclusion regions, we find that for heavy gluino masses the squark discovery reach is significantly reduced in Dirac gluino models relative to the Majorana case. However, if the squark and gluino masses are close the reach is similar in both scenarios. We also consider the electroweak fine tuning of theories observable at such a collider, and the impact of existing constraints from flavour and CP violating observables. Models with Majorana gluinos that are fine tuned to less than one part in 10,000 can typically be discovered or excluded, and Dirac models with tuning of one part in 1,000 can be probed. The flavour structure of Majorana models is highly constrained if they have observable squarks, while O(1) violation is possible in accessible Dirac models. In both cases new sources of CP violation must be very suppressed. Future collider searches can also give important information on possible dark matter candidates. We study the relation of this to indirect and direct detection searches, and find that if dark matter is a neutralino, a 100 TeV collider could probe the viable dark matter candidates in large classes of both Dirac and Majorana models.