An improved upper limit on the neutrino mass from a direct kinematic
  method by KATRIN
  We report on the neutrino mass measurement result from the first four-week
science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019.
Beta-decay electrons from a high-purity gaseous molecular tritium source are
energy analyzed by a high-resolution MAC-E filter. A fit of the integrated
electron spectrum over a narrow interval around the kinematic endpoint at 18.57
keV gives an effective neutrino mass square value of $(-1.0^{+0.9}_{-1.1})$
eV$^2$. From this we derive an upper limit of 1.1 eV (90$\%$ confidence level)
on the absolute mass scale of neutrinos. This value coincides with the KATRIN
sensitivity. It improves upon previous mass limits from kinematic measurements
by almost a factor of two and provides model-independent input to cosmological
studies of structure formation.
