The XENONnT experiment, located in the Gran Sasso underground laboratory, is primarily dedicated to the direct detection of WIMPs (Weakly Interacting Massive Particles), one of the most promising candidates for dark matter. Exploiting a 5.9 t liquid Xenon time projection chamber (LXe TPC), the experiment achieves unprecedented sensitivity to rare-event physics, extending its reach well beyond its primary dark matter search. 

This seminar focuses on additional breakthroughs enabled by XENONnT, including precision studies of the isotopes $^{212}$Pb, $^{214}$Pb, and $^{210}$Pb, which play crucial roles in background characterization. For the first time, direct measurements of the ground state branching ratios of $^{212}$Pb and $^{214}$Pb have been achieved, with precision levels exceeding those in existing literature.

Moreover, a physics-driven model has been developed to characterize the wall background induced by $^{210}$Pb, originating from radon decay products plating out onto the PTFE surfaces outlining the detector sensitive volume. This model not only advances our knowledge of radon daughter contamination but also validates fundamental aspects of LXe TPC operation, such as its spatial resolution and response at its borders.

All these findings from Lead isotopes studies provide critical insights into electron recoil and surface backgrounds, enhancing the sensitivity of current and future LXe TPC WIMP searches, and prove the versatility of LXe TPC technology, positioning XENONnT at the cutting edge of also the field of experimental precision nuclear physics.

In addition to these results exploiting XENONnT data, the seminar will briefly describe the neutrino mass sensitivity studies I have led in the HOLMES experiment framework. We demonstrated that by exploiting a non-standard pulse processing technique, the experimental throughput of the HOLMES experiment is increased leading to an enhancement on neutrino mass sensitivity of about 19%.

Click to watch talk here.