DSR-relativistic spacetime picture and the phenomenology of Planck-scale-modified time dilation

TL;DR

This paper investigates how Planck-scale modifications affect time dilation within DSR-relativistic spacetime, finding that such effects are too small for current experimental detection, unlike in LIV scenarios.

Contribution

The study provides new insights into DSR transformations, showing that modifications to time dilation are minimal and unlikely to be experimentally observable.

Findings

Time dilation cannot be modified in LIV scenarios.

DSR allows for modifications, but they are very small.

Modifications are too tiny for current experimental tests.

Abstract

The most active area of research in quantum-gravity phenomenology investigates the possibility of Planck-scale-modified dispersion relations, focusing mainly on two alternative scenarios: the "LIV" scenario, characterized by a specific mechanism of breakdown of relativistic symmetries, and the "DSR" scenario, which preserves overall relativistic invariance but with deformed laws of relativistic transformation. Two recent studies of modified dispersion relations, one relying on Finsler geometry and one based on heuristic reasoning, raised the possibility of potentially observable effects for time dilation and argued that this might apply also to the LIV and DSR scenarios. We observe that the description of Lorentz transformations in the LIV scenario is such that time dilation cannot be modified. The DSR scenario allows for modifications of time dilation, and establishing their magnitude required us to obtain novel results on the effects of finite DSR boosts in the spacetime sector, with results showing in particular that the modification of time dilation is too small for experimental testing.