Exploring light dark sectors

Author(s)

Gustavo Figueiredo Severiano Alves

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2025-08-21

Examining board members

Renata Zukanovich Funchal; Ivone Freire da Mota e Albuquerque; Roni Harnik; Orlando Luis Goulart Peres; Arman Esmaili Taklimi

• Advisor: Renata Zukanovich Funchal

Abstract

The question of how neutrinos acquire their masses remains one of the most compelling open problems in particle physics and a clear sign of physics beyond the Standard Model (SM). One well-motivated possibility is related to the existence of heavy neutrinosoften referred to as sterile neutrinos or heavy neutral leptons (HNLs). These particles could play a key role not only in generating neutrino masses, but also in determining the fundamental nature of neutrinos---whether they are Dirac or Majorana particles. HNLs naturally explain the smallness of light neutrino masses through the well-known seesaw mechanism. Incorporating them into the SM typically requires additional new particles, often pointing toward a richer structure beyond the SM. In this project, we investigate dark sectors beyond the SM, focusing on the phenomenology of HNLs. We aim to study their experimental signatures and assess the prospects for their detection in neutrino experiments. By exploring how HNLs can arise within ultraviolet-complete extensions of the SM, we also examine their potential role as a portal to broader new physics sectors, offering guidance for future searches for additional particles. (AU)

• FAPESP's process: 20/08096-0 - Exploring light dark sectors
• Grantee: Gustavo Figueiredo Severiano Alves
• Support Opportunities: Scholarships in Brazil - Doctorate