Challenging Spontaneous Quantum Collapse with the XENONnT Dark Matter Detector

Area of Science:

• Quantum mechanics
• Particle physics
• Astrophysics

Background:

• Dynamical quantum collapse models offer a potential solution to the quantum measurement problem.
• These models predict spontaneous radiation, detectable as X-ray emissions.
• Previous searches lacked the sensitivity to constrain model parameters effectively.

Purpose of the Study:

• To search for predicted X-ray radiation from dynamical quantum collapse.
• To set new experimental limits on the parameters of the Markovian continuous spontaneous localization (CSL) and Diósi-Penrose (DP) models.
• To test the validity of CSL models within their originally proposed parameter ranges.

Main Methods:

• Analysis of low-energy electronic recoil data (1-140 keV) from the XENONnT dark matter detector's first science run.
• Development of a novel analysis model incorporating charge cancellation effects in xenon atoms for X-ray spectra.
• Application of statistical methods to derive limits on model parameters.

Main Results:

• Established new world-leading limits on CSL and DP model parameters.
• Improved previous constraints by two orders of magnitude for CSL and a factor of five for DP.
• Experimentally excluded, for the first time, specific parameter ranges for CSL model strength and correlation length.

Conclusions:

• The XENONnT experiment provides the most stringent constraints to date on dynamical quantum collapse models.
• The results challenge the viability of CSL models within their originally proposed parameter space.
• This work demonstrates the potential of dark matter detectors for fundamental physics research beyond dark matter searches.