Probing Scalar-Neutrino and Scalar-Dark-Matter Interactions with PandaX-4T

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• Exotic scalar-mediated interactions may link neutrinos, dark matter, and the universe's expansion.
• Double beta decay experiments are sensitive probes of new physics beyond the Standard Model.
• The Hubble tension presents a significant discrepancy in measuring the universe's expansion rate.

Purpose of the Study:

• To perform the first direct spectral search for scalar-mediated neutrino self-interactions.
• To set the most stringent limits on these interactions for specific mediator mass ranges.
• To constrain cosmological models, including those addressing the Hubble tension and dark matter properties.

Main Methods:

• Utilized ^{136}Xe double beta decay data from the PandaX-4T experiment.
• Conducted a direct spectral analysis within the energy range of 20 to 2800 keV.
• Combined experimental constraints with existing cosmological data.

Main Results:

• Established the most stringent limits to date on scalar-mediated neutrino self-interactions for mediator masses below 2 MeV/c².
• Provided significant constraints on theoretical models proposing scalar mediators to resolve the Hubble tension.
• Derived constraints on dark matter-scalar interactions by assuming a common mediator.

Conclusions:

• Double beta decay experiments offer powerful constraints on fundamental physics, including neutrino and dark matter interactions.
• The findings challenge models that rely on specific scalar-mediated interactions to explain cosmological observations.
• This work highlights the interplay between particle physics experiments and cosmological puzzles.