How fast can protons decay?

TL;DR

This paper explores the possibility that proton decay rates may vary across space and time, suggesting that protons could decay much faster in certain regions or periods, challenging the assumption of their constant longevity.

Contribution

It introduces models and constraints indicating that proton lifetime can vary spatially and temporally, proposing potential signals and implications for fundamental physics.

Findings

Proton lifetime could be 15 orders of magnitude shorter in certain conditions.

Potential signals include terrestrial and astrophysical observations.

Models suggest possible long-range forces affecting proton decay.

Abstract

Current laboratory bounds imply that protons are extremely long-lived. However, this conclusion may not hold for all time and in all of space. We find that the proton lifetime can be $\sim 15$ orders of magnitude shorter in the relatively recent past on Earth, or at the present time elsewhere in the Milky Way. A number of terrestrial and astrophysical constraints are examined and potential signals are outlined. We also sketch possible models that could lead to spatial or temporal variations in the proton lifetime. A positive signal could be compelling evidence for a new long range force of Nature, with important implications for the limitations of fundamental inferences based solely on laboratory measurements.