Magnetic anomaly in UCN trapping: signal for neutron oscillations to parallel world?

  • Zurab BerezhianiEmail author
  • Fabrizio Nesti
Open Access


Present experiments do not exclude that the neutron n oscillates, with an appreciable probability, into its invisible degenerate twin from a parallel world, the so-called mirror neutron n′. These oscillations were searched experimentally by monitoring the neutron losses in ultra-cold neutron traps, where they can be revealed by the magnetic field dependence of nn′ transition probability. In this work we reanalyze the experimental data acquired by the group of A.P. Serebrov at Institute Laue–Langevin, and find a dependence at more than 5σ away from the null hypothesis. This anomaly can be interpreted as oscillation of neutrons to mirror neutrons with a timescale of few seconds, in the presence of a mirror magnetic field order 0.1 G at the Earth. This result, if confirmed by future experiments, will have deepest consequences for fundamental particle physics, astrophysics and cosmology.


Dark Matter Sterile Neutrino Hide Sector Baryon Asymmetry Ultracold Neutron 
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  1. 1.
    T.D. Lee, C.N. Yang, Question of parity conservation in weak interactions. Phys. Rev. 104, 254 (1956) ADSCrossRefGoogle Scholar
  2. 2.
    K. Nishijima, M.H. Saffouri, CP invariance and the shadow universe. Phys. Rev. Lett. 14, 205 (1965) ADSCrossRefGoogle Scholar
  3. 3.
    I.Yu. Kobzarev, L.B. Okun, I.Ya. Pomeranchuk, On the possibility of experimental observation of mirror particles. Sov. J. Nucl. Phys. 3, 837 (1966) Google Scholar
  4. 4.
    S.I. Blinnikov, M.Y. Khlopov, On possible effects of mirror particles. Sov. J. Nucl. Phys. 36, 472 (1982) Google Scholar
  5. 5.
    R. Foot, H. Lew, R.R. Volkas, A model with fundamental improper space-time symmetries. Phys. Lett. B 272, 67 (1991) ADSCrossRefGoogle Scholar
  6. 6.
    H.M. Hodges, Mirror baryons as the dark matter. Phys. Rev. D 47, 456 (1993) ADSCrossRefGoogle Scholar
  7. 7.
    Z. Berezhiani, D. Comelli, F.L. Villante, The early mirror universe: inflation baryogenesis, nucleosynthesis and dark matter. Phys. Lett. B 503, 362 (2001) ADSCrossRefGoogle Scholar
  8. 8.
    A.Y. Ignatiev, R.R. Volkas, Mirror dark matter and large scale structure. Phys. Rev. D 68, 023518 (2003) ADSCrossRefGoogle Scholar
  9. 9.
    Z. Berezhiani, P. Ciarcelluti, D. Comelli, F.L. Villante, Structure formation with mirror dark matter: CMB and LSS. Int. J. Mod. Phys. D 14, 107 (2005) ADSzbMATHCrossRefGoogle Scholar
  10. 10.
    L. Bento, Z. Berezhiani, Leptogenesis via collisions: the lepton number leaking to the hidden sector. Phys. Rev. Lett. 87, 231304 (2001) ADSCrossRefGoogle Scholar
  11. 11.
    L. Bento, Z. Berezhiani, Baryogenesis: the lepton leaking mechanism, in Proc. 11th Int. School on Particles and Cosmology (INR Press, Moscow 2001). arXiv:hep-ph/0111116 Google Scholar
  12. 12.
    L. Bento, Z. Berezhiani, Baryon asymmetry, dark matter and the hidden sector. Fortschr. Phys. 50, 489 (2002) zbMATHCrossRefGoogle Scholar
  13. 13.
    Z. Berezhiani, Mirror world and its cosmological consequences. Int. J. Mod. Phys. A 19, 3775 (2004) ADSzbMATHCrossRefGoogle Scholar
  14. 14.
    Z. Berezhiani, Through the looking-glass: Alice’s adventures in mirror world, in I. Kogan Memorial Collection ‘From Fields to Strings: Circumnavigating Theoretical Physics’, ed. by M. Shifman et al., vol. 3 (2005), pp. 2147–2195. arXiv:hep-ph/0508233 CrossRefGoogle Scholar
  15. 15.
    Z. Berezhiani, Unified picture of ordinary and dark matter genesis. Eur. Phys. J. Spec. Top. 163, 271 (2008) CrossRefGoogle Scholar
  16. 16.
    Z. Berezhiani, Marriage between the baryonic and dark matters. AIP Conf. Proc. 878, 195 (2006). arXiv:hep-ph/0612371 ADSCrossRefGoogle Scholar
  17. 17.
    Z. Berezhiani, Unified picture of the particle and sparticle masses in SUSY GUT. Phys. Lett. B 417, 287 (1998) ADSCrossRefGoogle Scholar
  18. 18.
    Z. Berezhiani, A.D. Dolgov, R.N. Mohapatra, Asymmetric inflationary reheating and the nature of mirror universe. Phys. Lett. B 375, 26 (1996) MathSciNetADSzbMATHCrossRefGoogle Scholar
  19. 19.
    Z. Berezhiani, Astrophysical implications of the mirror world with broken mirror parity. Acta Phys. Pol. B 27, 1503 (1996) ADSGoogle Scholar
  20. 20.
    R.N. Mohapatra, V.L. Teplitz, Structures in the mirror universe. Astrophys. J. 478, 29 (1997) ADSCrossRefGoogle Scholar
  21. 21.
    C.R. Das, L.V. Laperashvili, A. Tureanu, Cosmological constant in a model with superstring-inspired E(6) unification and shadow Theta-particles. Eur. Phys. J. C 66, 307 (2010) ADSCrossRefGoogle Scholar
  22. 22.
    C.R. Das, L.V. Laperashvili, H.B. Nielsen, A. Tureanu, Baryogenesis in cosmological model with superstring-inspired E 6 unification. Phys. Lett. B 696, 138 (2011) ADSCrossRefGoogle Scholar
  23. 23.
    C.R. Das, L.V. Laperashvili, H.B. Nielsen, A. Tureanu, Mirror world and superstring-inspired hidden sector of the Universe, dark matter and dark energy. Phys. Rev. D 84, 063510 (2011) ADSCrossRefGoogle Scholar
  24. 24.
    G. Dvali, G. Gabadadze, Nonconservation of global charges in the brane universe and baryogenesis. Phys. Lett. B 460, 47 (1999) ADSCrossRefGoogle Scholar
  25. 25.
    R. Foot, R.R. Volkas, Neutrino physics and the mirror world: How exact parity symmetry explains the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experiment. Phys. Rev. D 52, 6595 (1995) ADSCrossRefGoogle Scholar
  26. 26.
    Z. Berezhiani, R.N. Mohapatra, Reconciling present neutrino puzzles: sterile neutrinos as mirror neutrinos. Phys. Rev. D 52, 6607 (1995) ADSCrossRefGoogle Scholar
  27. 27.
    R. Foot, H. Lew, R.R. Volkas, Possible consequences of parity conservation. Mod. Phys. Lett. A 7, 2567 (1992) ADSCrossRefGoogle Scholar
  28. 28.
    E.K. Akhmedov, Z. Berezhiani, G. Senjanovic, Planck scale physics and neutrino masses. Phys. Rev. Lett. 69, 3013 (1992) ADSCrossRefGoogle Scholar
  29. 29.
    Z. Silagadze, Neutrino mass and the mirror universe. Phys. At. Nucl. 60, 272 (1997) Google Scholar
  30. 30.
    B. Holdom, Two U(1)’s and epsilon charge shifts. Phys. Lett. B 166, 196 (1986) ADSCrossRefGoogle Scholar
  31. 31.
    S.L. Glashow, Positronium versus the mirror universe. Phys. Lett. B 167, 35 (1986) ADSCrossRefGoogle Scholar
  32. 32.
    S.N. Gninenko, Limit on ‘disappearance’ of orthopositronium in vacuum. Phys. Lett. B 326, 317 (1994) ADSCrossRefGoogle Scholar
  33. 33.
    P. Crivelli et al., Positronium portal into hidden sector: a new experiment to search for mirror dark matter. J. Instrum. 5, P08001 (2010) CrossRefGoogle Scholar
  34. 34.
    R. Foot, A comprehensive analysis of the dark matter direct detection experiments in the mirror dark matter framework. Phys. Rev. D 82, 095001 (2010) ADSCrossRefGoogle Scholar
  35. 35.
    Z. Berezhiani et al., Strongly interacting mirror dark matter, CERN-PH-TH-2008-108 Google Scholar
  36. 36.
    Z. Berezhiani, L. Bento, Neutron–mirror neutron oscillations: how fast might they be? Phys. Rev. Lett. 96, 081801 (2006). arXiv:hep-ph/0507031 ADSCrossRefGoogle Scholar
  37. 37.
    Z. Berezhiani, L. Bento, Fast neutron–mirror neutron oscillation and ultra high energy cosmic rays. Phys. Lett. B 635, 253 (2006). arXiv:hep-ph/0602227 ADSCrossRefGoogle Scholar
  38. 38.
    Z. Berezhiani, More about neutron–mirror neutron oscillation. Eur. Phys. J. C 64, 421 (2009). arXiv:0804.2088 [hep-ph] ADSCrossRefGoogle Scholar
  39. 39.
    R.N. Mohapatra, S. Nasri, S. Nussinov, Some implications of neutron mirror neutron oscillation. Phys. Lett. B 627, 124 (2005). arXiv:hep-ph/0508109 ADSCrossRefGoogle Scholar
  40. 40.
    G. Dvali, M. Redi, Phenomenology of 1032 dark sectors. Phys. Rev. D 80, 055001 (2009). arXiv:0905.1709 [hep-ph] ADSCrossRefGoogle Scholar
  41. 41.
    M. Baldo-Ceolin et al., New experimental limit on neutron antineutron oscillations. Z. Phys. C 63, 409 (1994) ADSCrossRefGoogle Scholar
  42. 42.
    V.A. Kuzmin, CP violation and baryon asymmetry of the universe. JETP Lett. 12, 335 (1970) Google Scholar
  43. 43.
    R.N. Mohapatra, R.E. Marshak, Local B-L symmetry of electroweak interactions, Majorana neutrinos and neutron oscillations. Phys. Rev. Lett. 44, 1316 (1980) ADSCrossRefGoogle Scholar
  44. 44.
    Yu.N. Pokotilovski, On the experimental search for neutron–mirror neutron oscillations. Phys. Lett. B 639, 214 (2006). arXiv:nucl-ex/0601017 ADSCrossRefGoogle Scholar
  45. 45.
    D. Dubbers, M.G. Schmidt, The neutron and its role in cosmology and particle physics. Rev. Mod. Phys. 83, 1111 (2011) ADSCrossRefGoogle Scholar
  46. 46.
    B. Kerbikov, O. Lychkovskiy, Neutron–mirror neutron oscillations in a trap. Phys. Rev. C 77, 065504 (2008) ADSCrossRefGoogle Scholar
  47. 47.
    G. Ban et al., A direct experimental limit on neutron–mirror neutron oscillations. Phys. Rev. Lett. 99, 161603 (2007) ADSCrossRefGoogle Scholar
  48. 48.
    A. Serebrov et al., Experimental search for neutron–mirror neutron oscillations using storage of ultracold neutrons. Phys. Lett. B 663, 181 (2008) ADSCrossRefGoogle Scholar
  49. 49.
    I. Altarev et al., Neutron to mirror neutron oscillations in the presence of mirror magnetic fields. Phys. Rev. D 80, 032003 (2009) ADSCrossRefGoogle Scholar
  50. 50.
    K. Bodek et al., Additional results from the dedicated search for neutron mirror neutron oscillations. Nucl. Instrum. Methods Phys. Res. A 611, 141 (2009) ADSCrossRefGoogle Scholar
  51. 51.
    A. Serebrov et al., Search for neutron mirror neutron oscillations in a laboratory experiment with ultracold neutrons. Nucl. Instrum. Methods Phys. Res. A 611, 137 (2009) ADSCrossRefGoogle Scholar
  52. 52.
    K. Nakamura et al. (Particle Data Group), Review of particle physics. J. Phys. G 37, 075021 (2010) ADSCrossRefGoogle Scholar
  53. 53.
    A. Serebrov et al., UCN anomalous losses and the UCN capture cross-section on material defects. Phys. Lett. A 335, 327 (2005) ADSCrossRefGoogle Scholar
  54. 54.
    A.Y. Ignatiev, R.R. Volkas, Geophysical constraints on mirror matter within the Earth. Phys. Rev. D 62, 023508 (2000) ADSCrossRefGoogle Scholar
  55. 55.
    Z. Berezhiani, P. Geltenbort, S. Ivanov, A.P. Serebrov, O. Zimmer, Testing signal for neutron–mirror neutron oscillation in magnetic fields, ILL Research Proposal No. 3-14-303, 2011 Google Scholar
  56. 56.
    S. Raby et al., DUSEL theory white paper, e-print arXiv:0810.4551 [hep-ph]
  57. 57.
    Z. Berezhiani, A. Gazizov, Neutron oscillations to parallel world: earlier end to the cosmic ray spectrum? Phys. Rev. D. arXiv:1109.3725 [astro-ph.HE]

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© The Author(s) 2012

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Authors and Affiliations

  1. 1.Dipartimento di FisicaUniversità dell’AquilaCoppitoItaly
  2. 2.INFNLaboratori Nazionali Gran SassoAssergiItaly

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