2001/06/30 by Guy D. Moore, Ann E. Nelson · 2 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Noncommutative and Quantum Gravity Theories #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1126-6708/2001/09/023
published as JHEP 0109:023,2001 · 8 pages with 1 figure, JHEP style. References added, slight (superficial) changes
arxiv created 2001/09/11 · openalex publication_date 2001/09/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recently, interesting 4-D Lorentz violating models have been proposed, in which all particles have a common maximum velocity c, but gravity propagates (in the preferred frame) with a different maximum velocity cg ≠ c. We show that the case cg < c is very tightly constrained by the observation of the highest energy cosmic rays. Assuming a galactic origin for the cosmic rays gives a conservative bound of c-cg < 2 × 10-15 c; if the cosmic rays have an extragalactic origin the bound is orders of magnitude tighter, of order c-cg < 2 × 10-19 c.