Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the ...South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. No significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere.
We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrts(NN)=200 GeV. A large, approximately constant hadron suppression is observed in ...central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.
Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass ...distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.
In recent publications it has been pointed out that the α decay of transuranic elements in nuclear waste can be considerably speeded up by putting them into metals. The proposed mechanism is based on ...the effect of electron screening of radioactive nuclei (according to the Debye electron plasma model), which grows enhanced as temperature decreases. To verify the predicted phenomenon, half-lives of
253
Es nuclei implanted in a metallic iron foil were measured at the temperature from 4 K to 50 mK. The results agree with the room-temperature data reported in the literature; no temperature dependence of the half-life was found within the error of ≈2%.
In recent publications it has been pointed out that the alpha decay of transuranic elements in nuclear waste can be considerably speeded up by putting them into metals. The proposed mechanism is ...based on the effect of electron screening of radioactive nuclei (according to the Debye electron plasma model), which grows enhanced as temperature decreases. To verify the predicted phenomenon, half-lives of 253Es nuclei implanted in a metallic iron foil were measured at the temperature from 4 K to 50 mK. The results agree with the room-temperature data reported in the literature; no temperature dependence of the half-life was found within the error of asymp2%.
PDF