Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Still too small to be measured

Although the mass of the electron antineutrino is still eluding direct measurement, the KATRIN experiment with its huge spectrometer has pushed the sensitivity below a billionth of the proton mass.

Your institute does not have access to this article

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Effect of the neutrino mass on the beta decay spectrum.


  1. Cowan, C. L., Reines, F., Harrison, F. B., Kruse, H. W. & McGuire, A. D. Science 124, 103–104 (1956).

    ADS  Article  Google Scholar 

  2. Olive, K. et al. Chin. Phys. C 38, 090001 (2014).

    ADS  Article  Google Scholar 

  3. The KATRIN Collaboration Nat. Phys. (2022).

  4. Fermi, E. Z. Phys. 88, 161–177 (1934); English trans: Wilson, F. L. Am. J. Phys. 36, 1150–1160 (1968).

  5. Lubimov, V., Novikov, E., Nozik, V., Tretyakov, E. & Kosik, V. Phys. Lett. B 94, 266–268 (1980).

    ADS  Article  Google Scholar 

  6. Drexlin, G., Hannen, V., Mertens, S. & Weinheimer, C. Adv. High Energy Phys 2013, 293986 (2013).

    Article  Google Scholar 

  7. Capozzi, F. et al. Phys. Rev. D 101, 116013 (2020).

    ADS  Article  Google Scholar 

  8. Ashtari Esfahani, A. et al. J. Phys. G 44, 054004 (2017).

    ADS  Article  Google Scholar 

  9. Gastaldo, L. et al. Eur. Phys. J. Spec. Top. 226, 1623–1694 (2017).

    Article  Google Scholar 

  10. Alpert, B. et al. Eur. Phys. J. C 75, 112 (2015).

    ADS  Article  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Angelo Nucciotti.

Ethics declarations

Competing interests

The author declares no competing interests.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nucciotti, A. Still too small to be measured. Nat. Phys. 18, 128–129 (2022).

Download citation

  • Published:

  • Issue Date:

  • DOI:

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing