Searching for the dark sector: New probes at current and future experiments

The nature of dark matter suggests that our understanding of our fundamental particles is incomplete. There could be a dark sector of particles that are not charged under Standard Model gauge symmetries that would interact very weakly with Standard Model particles. Particles in the dark sector could be used to explain the nature of dark matter as well as other theory problems that remain in particle physics. In this thesis, I will explore a sample of dark sector particle models and discuss new methods to search for these particles at upcoming experiments. First, I will motivate three dark sector particles - the dark photon, millicharged particle, and axion - and discuss their current detection efforts and constraints. Then I will discuss a new experimental proposal to detect axion dark matter using multiple haloscopes. Currently axion haloscope experiments only have information about the dark matter speed distribution, but with multiple haloscopes they gain additional information about the dark matter velocity distribution. Next, I will discuss a new production channel for dark photons at proton beam dump experiments through charged pion bremsstrahlung. Proton beam dump experiments produce many charged pions which can scatter off the nuclei in the target and radiate off a dark photon. The large number of high energy charged pions can potentially produce a significant number of GeV-scale dark photons at beam dump experiments. Lastly, we will extend this production mechanism to millicharged particles and heavy axions. We will calculate the number of signal events we can detect for each particle and compare the signal events from charged pion scattering to existing projections and constraints.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Nguyen, Rachel

Contributors dc:contributor

• Kahn, Yonatan
• Shelton, Jessie
• Goldschmidt, Elizabeth
• Yunes, Nicolas

• Dark Sector
• Particle Physics
• Beyond Standard Model
• Dark Matter

Statement dc:rights

• Copyright 2024 Rachel Nguyen

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127136

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127136