Direct search for keV-sterile neutrino in nuclear decay. Troitsk nu-mass (Mini-review)
A. A. Nozik+*, V. S. Pantuev+
+Institute for Nuclear Research Russian Academy of Sciences, 117312 Moscow, Russia
*Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
We present a brief review of experimental status in searching
hypothetical sterile neutrino in nuclear decay in laboratory testing. The
main idea is based on search for an additional small component in the
β-spectrum or a shift in the internal electron conversion energy.
For example, in a three-body β-decay it looks like a kink in the
continuous spectrum shifted by the value of sterile neutrino mass from
the spectrum endpoint.
After a short general motivation for such a search we discuss the
way how to find sterile neutrino in the nuclear β-decay and present
the current status of upper limits on sterile neutrino mixing with
electron antineutrino. The advantages and problems arising in the precise
measurements of β-spectrum are demonstrated on the basis of the
"Troitsk nu-mass" experiment by presenting the all measurement and
analysis procedures in details. At the end we discuss the nearest future
of such experiments.