Evidence of Antineutrinos from Distant Reactors Using Pure Water at SNO

The SNO+ Collaboration reports the first evidence of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240 km away in Ontario, Canada. This analysis uses events with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods are used to distinguish reactor antineutrinos from background events in 190 days of data and yield consistent evidence for antineutrinos with a combined significance of 3.5σ.

Testing Diffusion of Cosmic Rays in the Heliosphere with Proton and Helium Data from AMS

After six years of continuous observations in space, the Alpha Magnetic Spectrometer experiment has released new data on the temporal evolution of the proton and helium fluxes in cosmic rays. These data revealed that the ratio between proton and helium fluxes at the same value of rigidity R=p/Z (momentum/charge ratio) is not constant at R≲3  GV. In particular, the ratio is found to decrease steadily during the descending phase of Solar Cycle 24 toward the next minimum. We show that such a behavior is a remarkable signature of the β×λ(R) dependence in the diffusion of cosmic rays in heliosphere, where β is their adimensional speed and λ(R) is their mean free path, a universal function of rigidity for all nuclei. This dependence is responsible for distinctive charge or mass dependent effects in the time-dependent modulation of low-rigidity particles.