Challenging Spontaneous Quantum Collapse with XENONnT

TL;DR

This paper reports a search for X-ray radiation from dynamical quantum collapse models using XENONnT data, setting new stringent limits that challenge previous theoretical proposals and exclude original model parameters.

Contribution

It introduces a novel analysis that accounts for cancellation effects in emitted spectra, providing the first experimental constraints on certain collapse model parameters.

Findings

Set new world-leading limits on collapse model parameters

Excluded original values for the CSL model's strength and correlation length

Improved previous constraints by two orders of magnitude and a factor of five

Abstract

We report on the search for X-ray radiation as predicted from dynamical quantum collapse with low-energy electronic recoil data in the energy range of 1-140 keV from the first science run of the XENONnT dark matter detector. Spontaneous radiation is an unavoidable effect of dynamical collapse models, which were introduced as a possible solution to the long-standing measurement problem in quantum mechanics. The analysis utilizes a model that for the first time accounts for cancellation effects in the emitted spectrum, which arise in the X-ray range due to the opposing electron-proton charges in xenon atoms. New world-leading limits on the free parameters of the Markovian continuous spontaneous localization and Di\'osi-Penrose models are set, improving previous best constraints by two orders of magnitude and a factor of five, respectively. The original values proposed for the strength and the correlation length of the continuous spontaneous localization model are excluded experimentally for the first time.