Abstract: Borexino is a large liquid scintillator detector that has been taking solar neutrino data at the Gran Sasso laboratory in Italy since 2007. The 300-ton liquid scintillator detector measures solar neutrinos by detection of recoil electrons from neutrino-electron elastic scattering. Its signature feature is ultra-low background that enabled measurement of neutrinos below the 3-MeV “background wall.” The low-background breakthrough enabled the first direct measurement of the of mono-energetic 862 keV 7Be neutrinos, followed by measurement of the 1.44 MeV pep neutrinos and 8B neutrinos.
Scintillator purification in 2010-2011 reduced background further to improve sensitivity to pp and CNO neutrinos. With pp-neutrino data acquisition completed, scintillator purification will restart soon to lower background further for first attempt to detect and measure rare CNO neutrinos. Measurement of solar neutrinos over the full energy spectrum explores the MSW transition from vacuum to matter-effect neutrino oscillations, and may reveal new physics. The measurements also provide the most complete study of the nuclear fusion reactions that power the Sun and stars. I will also describe planned experiments with Borexino to search for short-baseline neutrino oscillations with intense neutrinos sources of 51Cr and 144Ce.
Time: 4:00 – 5:00pm
Location: Physics/Astrophysics Bldg., Kistler Conference Room 102/103 (Map)
(Light refreshments available 4:00pm; Presentation begis 4:15pm)
Open to All