Working with data from the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy, a group of researchers demonstrated that solar neutrinos may be measured with both directional and energy sensitivity. Two teams within the group have authored articles outlining the group’s work, one of which has been published in Physical Review D and the other in Physical Review Letters.
The Borexino detector was initially suggested in 1986, and its construction was finished in 2004. It started releasing data to academics in May of 2007. Its goal was to study neutrino fluxes in proton-proton chains. The detector, which is presently being demolished, was constructed using 280 metric tons of radio-pure liquid scintillator protected by a layer of water. Solar neutrinos reflected off electrons in the scintillator, and the light emitted was detected by sensors bordering the tank.
Data from the Borexino detector was an outstanding source of high-resolution sensitivity data down to low energy thresholds throughout the most of its life, but it provided nothing in the way of directional trajectories. The researchers discovered a technique to combine data from the detector with data from another detector to offer trajectory information in this new endeavour.
The other detector was the Super Kamiokande detector in Japan, which was able to analyze the Cherenkov radiation emitted by electrons as they traveled in its massive tank of water, so revealing their trajectory. The Borexino researchers re-analyzed past data at their laboratory by connecting it with Cherenkov photons and known sun locations; in doing so, they discovered peaks in the data they represented. They then used those peaks to create computer simulations that allowed them to separate solar-neutrino events from background noise, and they discovered that they were able to identify real events, which strongly suggested they had detected Cherenkov photons, which provided them with directional information about the neutrinos. They believe their findings will open up new avenues for researching the sun’s carbon-nitrogen-oxygen cycle, as well as enhance the outcomes of searches for uncommon nuclear processes.