Evidence for x Rays From Sources Outside the Solar System by Riccardo Giacconi and others Created 2026-10-18 Updated 2026-11-05
Phys. Rev. Lett. 9:439–443.
Variation of the Rate of Decay of Mesotrons with Momentum by Bruno Rossi and David B. Hall Created 2026-10-20 Updated 2026-11-05
Bruno Rossi and David B. Hall, Physical Review 59, 223–228 (1941). The primary experiment compared more and less penetrating cosmic-ray particle populations and found momentum-dependent decay rates compatible with relativistic moving-clock rates.