Seminar by Mr. Chi-Ho LAM (University of Pittsburgh)

Neutrino oscillation experiments have firmly established that neutrinos have mass. Yet, the absolute mass scale remains unknown, a gap in the Standard Model with implications for the origin of neutrino mass, the possible existence of right-handed neutrinos, and whether neutrinos are their own antiparticles. Cosmological surveys place model-dependent bounds on the sum of neutrino masses, while direct kinematic measurements of tritium beta decay offer a model-independent probe by resolving the characteristic distortion of the beta decay spectrum near the endpoint. The state-of-the-art KATRIN experiment has placed an upper limit of 450 meV/c² and is expected to reach 300 meV/c². However, conventional MAC-E filter spectrometers such as KATRIN are approaching their limits in terms of scalability and systematics. Project 8 is the next-generation experiment, aiming to overcome this barrier using Cyclotron Radiation Emission Spectroscopy (CRES) to probe neutrino mass down to 40 meV/c², covering the inverted mass ordering completely.This talk will present Project 8's first neutrino mass measurement using CRES, and highlight recent efforts to develop the technique toward sub-eV sensitivity: resonant-cavity detection for improved statistics and energy resolution, and atomic tritium source development to eliminate molecular final-state broadening. I will also discuss Project 8's sensitivity to secondary physics signals, including sterile neutrinos and the cosmic neutrino background, and an outlook on the path toward a model-independent measurement capable of reaching the 40 meV/c² sensitivity target.