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Title: Testing Lorentz invariance of dark matter

We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.
Authors:
 [1] ; ;  [2]
  1. Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland)
  2. Faculty of Physics, Moscow State University, Vorobjevy Gory, 119991 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22279666
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2012; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BARYONS; COMPARATIVE EVALUATIONS; COSMOLOGY; COUPLING; DEGREES OF FREEDOM; DENSITY; EQUIVALENCE PRINCIPLE; LORENTZ INVARIANCE; MASS; NONLUMINOUS MATTER; PERTURBATION THEORY; VECTOR FIELDS