Transcript Neutrinos from the primary proton-proton fusion process in the sun

Neutrinos from the primary protonproton fusion process in the Sun
Sequence of nuclear fusion reactions
defining the pp chain in the Sun
• pp neutrinos constitute
nearly the entirety of solar
neutrino flux
• Secondary neutrinos
observed. (Oscillation)
• pp neutrinos elude direct
detection (pep neutrinos)
• Borexino Detector at San
Grasso Laboratory (Italy)
• Observed pp neutrinos for
the first time, confirming
our understanding of the
workings of our Sun
“Neutrinos from the primary proton-proton fusion process in the Sun”
Borexino Collaboration, Nature 512, 383 (2014)
Energy Spectrum/Borexino Detector
• Solar Neutrino Energy
Spectrum
• Fortunate energy spacing
• Carbon-14 Contamination
• Electron-Neutrino Elastic
Scattering (Emax=264keV)
• Expected 131±2 counts
per day per 100 ton
• 408 days of data
• Actual 148±13 ±12
Neutrino Oscillation/Energy Spectra
• Neutrino Oscillation
• Mikheyev-SmirnovWolfenstein Large-MixingAngle solution (MSW-LMA)
• Different scattering cross
sections
• Distinguishable at low
energies (C-14 and pp)
• “Pile-up events”
• 5.98 ∗ 1010 𝑐𝑚−2 𝑠 −1 𝑆𝑆𝑀
• 6.6 ± (0.7) ∗
1010 𝑐𝑚−2 𝑠 −1
• Future?