{
  "annotation_id": "c732cd41-23e5-44a9-adfe-da0a6d3e4467",
  "date_created": "2026-03-02T18:01:20.663000Z",
  "date_modified": "2026-03-02T18:01:20.663000Z",
  "file_hash": "02e89a21781a0ba0a2e3b43782d95e9d651633955b9a8665348e214bfcb592e9",
  "private": false,
  "record": {
    "abstract": "If textbook Lorentz invariance is actually a property of the equations\ndescribing a sector of the excitations of vacuum above some critical distance\nscale, several sectors of matter with different critical speeds in vacuum can\ncoexist and an absolute rest frame (the vacuum rest frame) may exist without\ncontradicting the apparent Lorentz invariance felt by \"ordinary\" particles\n(particles with critical speed in vacuum equal to $c$ , the speed of light).\nThe sectorial Lorentz symmetry may be only a low-energy limit, in the same way\nas the relation $\\omega $ (frequency) = $c_s$ (speed of sound) $k$ (wave\nvector) holds for low-energy phonons in a crystal. We study the consequences of\nsuch a scenario, using an ansatz inspired by the Bravais lattice as a model for\nsome vacuum properties. It then turns out that: a) the Greisen-Zatsepin-Kuzmin\ncutoff on high-energy cosmic protons and nuclei does no longer apply; b)\nhigh-momentum unstable particles have longer lifetimes than expected with exact\nLorentz invariance, and may even become stable at the highest observed cosmic\nray energies or slightly above. Some cosmological implications of superluminal\nparticles are also discussed.",
    "arxiv_id": "physics/9704017",
    "authors": [
      "Luis Gonzalez-Mestres"
    ],
    "categories": [
      "physics.gen-ph"
    ],
    "title": "Vacuum Structure, Lorentz Symmetry and Superluminal Particles",
    "url": "https://arxiv.org/abs/physics/9704017"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "6db6a834-5252-4ac3-9e33-d80bbd7f0d0a",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}