We performed a search for any sign of an additional neutrino mass state in β-electron spectrum based on data reanalysis of direct electron antineutrino mass measurements in Tritium beta-decay in the ...Troitsk nu-mass experiment. The existing data set allows us to search for such a state in the mass range up to 100 eV. The lowest value at a 95% C.L. upper limit for the contribution of a heavy eigenstate into electron neutrino is around or less than 1% for masses above 20 eV.
The paper describes methods and presents results of the Troitsk Nu-mass experiment spectrometer cleanup, which inner volume (40 m3) and surfaces (160 m2) was contaminated by 4.4 GBq of tritium. The ...Troitsk Nu-mass experiment of Institute for Nuclear Research of Russian Academy of Sciences, Moscow, is designed to measure the spectrum of electrons from tritium decays in order to search for hypothetical particles - sterile neutrinos. As a result of equipment failure, the spectrometer internal volume was contaminated with tritium. The contamination made measurements impossible and the research program stopped. The methods of vacuum extraction, hydrogen soaks, and water vapour soaks were used for cleanup. As a result of detritiation, the background level of the main detector of the Troitsk Nu-mass spectrometer decreased by more than 10 times, which made it possible to resume work. The results are consistent with the data obtained earlier for volumes in normal conditions in the air and can be used for planning work on detritiation of similar installations.
The most recent physics results obtained at the Relativistic Heavy Ion Collider (RHIC) are surveyed. The survey is devoted to considering
p
+
p
, Cu + Cu, and Au + Au systems of colliding nuclei at ...c.m. energies of √
s
NN
= 200, 62.4, and 22.4 GeV. The results obtained within the first years of collider operation are discussed. New data on the production of high-transverse-momentum particles are presented. Manifestations of collective flows, such as the radial and elliptic flows, as well as the formation of a shock wave and a ridge, are considered. The results concerning heavy-quark production are also discussed.
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