First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment.

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• The nature of dark matter remains a significant mystery in physics.
• Weakly Interacting Massive Particles (WIMPs) are leading candidates for dark matter.
• Previous experiments have searched for WIMPs, but direct detection remains challenging.

Purpose of the Study:

• To conduct the first search for WIMP-induced nuclear recoils using the XENONnT experiment.
• To set new limits on WIMP-nucleon cross sections, improving upon previous results.
• To investigate the potential for detecting dark matter in the form of WIMPs.

Main Methods:

• Utilizing a two-phase time projection chamber with a 5.9-ton liquid xenon target.
• Achieving unprecedentedly low concentrations of ^{85}Kr and ^{222}Rn in the liquid xenon.
• Performing a blind analysis of nuclear recoil events within a specific energy range (3.3–60.5 keV).

Main Results:

• No significant excess of nuclear recoil events was observed.
• A minimum upper limit on the spin-independent WIMP-nucleon cross section was set at 2.58×10^{-47} cm² for a WIMP mass of 28 GeV/c² (90% CL).
• Improved limits and sensitivity for WIMP masses compared to the XENON1T experiment were achieved.

Conclusions:

• The XENONnT experiment has provided the most stringent limits to date for WIMP-nucleon interactions.
• The results constrain WIMP models and guide future dark matter searches.
• Further analysis with increased exposure will enhance the sensitivity of XENONnT.