English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report the results of the second measurement campaign of the KarlsruheTritium Neutrino (KATRIN) experiment. KATRIN probes the effective electronanti-neutrino mass, $m_{\nu}$, via a high-precision measurement of the tritium$\beta$-decay spectrum close to its endpoint at $18.6\,\mathrm{keV}$. In thesecond physics run presented here, the source activity was increased by afactor of 3.8 and the background was reduced by $25\,\%$ with respect to thefirst campaign. A sensitivity on $m_{\nu}$ of $0.7\,\mathrm{eV/c^2}$ at$90\,\%$ confidence level (CL) was reached. This is the first sub-eVsensitivity from a direct neutrino-mass experiment. The best fit to thespectral data yields $m_{\nu}^2 = (0.26\pm0.34)\,\mathrm{eV^4/c^4}$, resultingin an upper limit of $m_{\nu}<0.9\,\mathrm{eV/c^2}$ ($90\,\%$ CL). By combiningthis result with the first neutrino mass campaign, we find an upper limit of$m_{\nu}<0.8\,\mathrm{eV/c^2}$ ($90\,\%$ CL).

First direct neutrino-mass measurement with sub-eV sensitivity