Speaker
Description
Lorentz invariance may be modified in quantum gravity scenarios, potentially leading to observable effects even far below the Planck scale. Ultra-high-energy cosmic rays provide a unique laboratory to probe such deviations. In this contribution, we exploit, for the first time, fluctuations in the muon content of extensive air showers measured at the Pierre Auger Observatory to constrain Lorentz invariance violation in the hadronic sector. The resulting bounds are the most stringent to date and are obtained without assumptions on the mass composition of ultra-high-energy cosmic rays. These results establish muon fluctuations as a powerful and complementary observable, opening a new window to probe Lorentz invariance in previously unexplored regions of parameter space.
