Sterile neutrino

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The sterile neutrino is a hypothetical elementary particle that is not subject to the fundamental interactions of the Standard Model , but only to gravity and possibly as yet unknown interactions. It is a right-handed neutrino . Right-handed neutrinos could be Majorana fermions if they have a mass of marjorana.

Such particles belong to a singlet - representation of the strong and the weak interaction ; their weak hypercharge , their weak isospin, and their electrical charge are each zero. In a large unified theory (GUT) such as the Georgi-Glashow model, they interact via gauge bosons , which in ordinary, i.e. H. relatively low, energies are very strongly suppressed because of their extremely high mass. In the case of supersymmetry , the sterile neutrino would have a left-handed super partner , also called a sterile sneutrino (the normal neutrino is left-handed and the normal sneutrino is right-handed).

The effects of the existence of sterile neutrinos depend heavily on their mass. The existence of light sterile neutrinos, the mass of which is comparable to that of the known neutrinos, is often discussed in connection with the reactor neutrino anomaly, the accelerator experiments LSND and MiniBooNE and the results of measurements with neutrino sources. The experimental data in this context is not yet clear. Current findings from MiniBooNE indicate results that are not compatible with the standard model, but can be explained by the existence of sterile neutrinos.

If they are significantly heavier than the known neutrinos, sterile neutrinos can generate the masses of light neutrinos through the Seesaw mechanism and thus solve one of the great puzzles of particle physics . Heavy sterile neutrinos could also explain the (cold or warm) dark matter or the baryon asymmetry of the universe through leptogenesis . Such heavy neutrinos can be searched for at particle accelerators, provided their mass is in the range of the achievable collision energies.

See also

Individual evidence

  1. ^ Marco Drewes: The phenomenology of right handed neutrinos . In: International Journal of Modern Physics E . tape 22 , no. 8 , 2013, p. 1330019–593 , doi : 10.1142 / S0218301313300191 , arxiv : 1303.6912 , bibcode : 2013IJMPE..2230019D .
  2. ^ G. Mention et al .: The Reactor Antineutrino Anomaly . In: Phys. Rev. D . tape 83 , no. 7 , 2011, doi : 10.1103 / PhysRevD.83.073006 , arxiv : 1101.2755 .
  3. ^ J. Kopp et al .: Sterile Neutrino Oscillations: The Global Picture . In: JHEP . tape 2013 , no. 50 , 2013, doi : 10.1007 / JHEP05 (2013) 050 , arxiv : 1303.3011 .
  4. ^ AA Aguilar-Arevalo et al .: Significant Excess of ElectronLike Events in the MiniBooNE Short-Baseline Neutrino Experiment . In: Phys. Rev. Lett. tape 121 , no. 22 , 2018, doi : 10.1103 / PhysRevLett.121.221801 , arxiv : 1805.12028 .

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