2009/05/31 by I. Altarev, C. A. Baker, C.A. Baker +50
Physics and Astronomy · #Atomic and Subatomic Physics Research #Atomic physics #CPT symmetry #Condensed matter physics #Dark Matter and Cosmic Phenomena #Dipole #Larmor precession #Lorentz covariance #Lorentz transformation #Magnetic field #Neutron #Noncommutative and Quantum Gravity Theories #Nuclear physics #Physics #Precession #Quantum electrodynamics #Quantum mechanics #Spin (aerodynamics) #Ultracold neutrons #nucl-ex
paper · pdf · doi:10.1103/physrevlett.103.081602
published as Phys.Rev.Lett.103:081602,2009 · 4 pages, 3 figures accepted for publication in Phys. Rev. Lett
arxiv created 2009/07/23 · openalex publication_date 2009/08/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and 199Hg atoms, is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b_\ensuremath⊥<2\ifmmode×\else\texttimes\fi10^\ensuremath-20 eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |gn|<0.3 eV/c2 m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |gn|<3\ifmmode×\else\texttimes\fi10^\ensuremath-4 eV/c2 m.