Signatures of supermassive charged gravitinos in liquid scintillator detectors

TL;DR

This paper proposes a novel detection method for supermassive charged gravitinos in liquid scintillator detectors like JUNO and DUNE, using photon 'glow' signals caused by their passage, supported by quantum-chemical cross section calculations.

Contribution

It introduces a new detection technique for supermassive charged gravitinos based on photon emission signatures in liquid detectors, combining particle physics and quantum chemistry methods.

Findings

Calculated excitation cross sections of LAB by gravitinos.

Simulated detector signals showing distinctive photon 'glow' signatures.

Demonstrated the feasibility of detecting such particles with upcoming experiments.

Abstract

In a previous work [K.A. Meissner and H. Nicolai, Eur. Phys. J. C {\bf 84}, 269 (2024)], two of the present authors have suggested possible experimental ways to search for stable supermassive particles with electric charges of $\cO(1)$ in upcoming underground experiments, in particular the new Jiangmen Underground Neutrino Observatory (JUNO) experiment. In the current paper, we present a detailed analysis of the specific signature of such gravitino-induced events for the JUNO detector and for upcoming liquid argon detectors like DUNE (Deep Underground Neutrino Experiment). The proposed method of detection relies on the ``glow'' produced by photons during the passage of such particles through the detector liquid, which would last for about a few to a few hundred microseconds depending on its velocity and the track. The cross sections for electronic excitation of the main component of the scintillator liquid, namely linear alkylbenzene (LAB), by the passing gravitino are evaluated using quantum-chemical methods. The results show that, if such particles exist, the resulting signals would lead to a unique and unmistakable signature, for which we present event simulations as they would be seen by the JUNO or DUNE photomultipliers. Our analysis brings together two very different research areas, namely fundamental particles physics and the search for a fundamental theory on the one hand, and methods of advanced quantum chemistry on the other.