Speaker
Description
The XENONnT experiment utilizes a dual‑phase liquid xenon (LXe) time projection chamber (TPC) to search for dark matter and other rare events. In addition to its primary nuclear-recoil (NR) search channel, XENONnT has achieved unprecedentedly low background rates in the electron-recoil (ER) channel. With extensive mitigation and active reduction efforts, the dominant ER background from radon and krypton has been reduced to levels comparable to the non-shieldable background induced by proton–proton (pp) chain solar neutrinos, effectively entering the irreducible neutrino background regime. This low ER background allows competitive probes of solar axions, axion‑like particles, and dark photons as dark matter candidates. The talk will summarize the key techniques that enabled this performance, including the cryogenic distillation column that reduced the krypton level below 100 ppq in Science Run 0 and the continuous removal system that reached an order of 1 $\mu$Bq/kg radon level in Science Run 1. The talk will also cover the high-precision measurement methods of the ultra‑low backgrounds in the TPC, including the Rare Gas Mass Spectrometer (RGMS) for $^{Nat}$Kr and dedicated alpha analysis on radon calibrations for $^{222}$Rn/$^{220}$Rn. Finally, this talk will report the latest XENONnT results on ER dark matter channels, on rare event channels from other Standard/Beyond-Standard Model signals, as well as on solar neutrino interaction measurements.
This work is supported by BMFTR under project number 05A23PM1.
| Main Contribution topic | Direct detection |
|---|---|
| Secondary contribution topic | Astrophysical observations |