The Ghost Particle neutrinos

How We Caught the Neutrino, and Why It Changes Identity Every second, about 65 billion neutrinos from the Sun pass through each square centimeter of your thumb, day and night. This is the detective story of how physicists inferred them from a few missing electron-volts in beta decay, caught them at a nuclear reactor in 1956, and then discovered that they change identity on the way from the Sun, which means they have mass. You can also hear the physics. Beta decay is played as notes whose pitch is the electron’s energy; the 1956 reactor experiment as clicks and delayed pairs of clicks; the Sun’s acoustic oscillations sped up 100,000 times; neutrino oscillation as two tones beating; and a sonic boom, the sound version of Cherenkov light. Every sound and every moving graph is computed from the same equations and parameters as the pictures: exact solutions of the wave equation, a numerical wave-equation simulation, and a numerical solution of neutrino propagation through the Sun. CHAPTERS 0:00 A puzzle on your thumbnail 0:48 1914: the crime scene 1:55 The energy really is missing 2:53 1930: Pauli's desperate remedy 3:31 1933: Fermi's theory 4:21 1934: 'No practically possible way' 4:44 1956: the stakeout 6:31 Three flavors 7:06 The Sun's missing neutrinos 8:11 The Sun's alibi 8:46 The twist: oscillation 10:10 Matter changes the rules 10:47 1998: Super-Kamiokande 12:09 2002: SNO closes the case 12:51 Open case files 15:11 Back to your thumb