Search for mirror dark matter in a laboratory experiment with ultracold neutrons

Source: arXiv


Mirror matter is considered as a candidate for dark matter. To investigate this possibility an experimental search for neutron - mirror neutron transitions has been carried out using storage of ultracold neutrons in a trap with different magnetic fields. As a result, a new limit for the neutron - mirror neutron oscillation time tau_osc has been obtained, tau_osc >= 448 s (90% C.L.). As a side result, some restriction of the presence of a mirror magnetic field in the range 0 - 1200 nT has been obtained.

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Available from: M. S. Lasakov, Mar 20, 2014
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    ABSTRACT: Physical processes involving weak interactions have mirror images which can be mimicked in the natural universe only by exchanging matter and antimatter. This experimental observation is easily explained by the hypothesis that spatial inversion exchanges matter and antimatter. Yet according to conventional theory, the parity operator P does not exchange matter and antimatter but instead yields phenomena which have never been observed. We examine the conventional derivation of the Dirac parity operator and find that it incorrectly identifies the matrices associated with probability density (γ 0 rather than the identity matrix I) and current (γ i rather than γ 5σ i ). This illusory functional dependence incorrectly requires that γ 0 preserve its sign under spatial inversion. This requirement results in a mixed-parity vector space defined relative to velocity, which is otherwise isomorphic to the spatial axes. We derive a new spatial inversion operator M (for mirroring) by introducing a pseudoscalar unit imaginary and requiring that for any set of orthogonal basis vectors, all three must have the same parity. The M operator is a symmetry of the Dirac equation. It exchanges positive and negative energy eigenfunctions, consistent with all experimental evidence of mirror symmetry between matter and antimatter. This result provides a simple reason for the apparent absence in nature of mirror-like phenomena, such as right-handed neutrinos, which do not exchange matter and antimatter. A new time reversal operator B (for backward) is also derived to be consistent with the geometry of the polar vectors inverted by the M operator.
    Preview · Article · Jun 2011 · Advances in Applied Clifford Algebras