Samantha Pagan successfully defends thesis “Physics on the keV Energy Scale with CUORE: A Search for Solar Axions”

October 18, 2024

On October 1, Samantha Pagan successfully defended the thesis “Physics on the keV Energy Scale with CUORE: A Search for Solar Axions” (advisor: Karsten Heeger).

Pagan explained, “Two cosmic scale questions in physics that we’ve yet to answer is how our universe formed to be made of matter (instead of its counterpart anti-matter, or even formed at all) and the nature of dark matter. During my PhD, I worked on the CUORE (The Cryogenic Underground Observatory for Rare Events) collaboration to study both of these questions.”

Pagan continued, “CUORE is an experiment at Gran Sasso National Laboratory in L’Aquila, Italy, that is an array of 988 TeO2 crystals, operated at about ~10 mK, which detect particle interactions from small rises in temperature in the crystals. During my PhD, I’ve been on the main analysis team of two of CUORE’s flagship searches for neutrinoless double beta decay, an ultra-rare proposed decay, which is a process that creates matter and helps study the question of why our universe is made of matter.”

“For my dissertation work, I have also mainly focused on developing analysis methods and performing the first studies of CUORE data at the keV scale. In this energy region, multiple searches for dark matter can be completed, enabling CUORE to probe questions about the nature of dark matter. The final part of my thesis includes a preliminary search for solar axions, a dark matter candidate, on a subset of CUORE data. This work demonstrated the potential of CUORE’s physics program at keV energies and the current unknowns and limitations. A phase of CUORE after it completes standard data taking is planned to be optimized for low-energy studies, and this work also informs improvements and possibilities for this stage.”

Pagan will be staying at Wright Lab as a postdocdoral associate for Karsten Heeger in the CUORE/CUPID group and transitioning to a new position next year.

Thesis Abstract: Foundational discoveries in particle physics and astronomy from the early 1900s to the 1930s led to the development of the Standard Model of particle physics in the 1970s and the Standard Cosmological Model in the 2000s. These theories describe the interactions of fundamental particles and the universe’s evolution. However, the explanations of the matter-antimatter asymmetry of the universe and the composition of dark matter remain unresolved questions that span both Standard Models. The Cryogenic Underground Observatory for Rare Events (CUORE), a tonne-scale experiment of 988 cryogenic calorimeters, investigates these questions through its primary search for neutrinoless double beta decay (0νΒΒ) and direct dark matter detection.

Thesis committee: Karsten Heeger (advisor), Reina Maruyama, Laura Havener, Ian Moult