Neutrina Fade: Neutrino Ghost Matter
Nuclear & Particle Physics arc, page 174 of 193. Back to The Pixelated Physics Universe
Who they are
Right now, tens of billions are passing through your thumbnail. About 65 billion solar neutrinos cross each square centimetre every second. Pauli proposed them in 1930; Cowan and Reines caught one in 1956. Neutrinos change flavour as they travel, which is only possible if they have mass. We see them through the Cherenkov light of the electrons and muons they knock loose. Neutrina Fade on a pixel-art unisex tee; equation, symbols and sources in the panel below.
Neutrina Fade is a character of the Nuclear & Particle Physics arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
A charged particle moving through water faster than light moves in water gives off a cone of blue Cherenkov light, at an angle set by its speed and the refractive index. Neutrino detectors see this glow from the particles that neutrinos knock loose, and the second formula describes how neutrinos change flavour as they travel.
$$ \begin{gathered} \cos\theta_C = \frac{1}{n\beta} \\ P_{\nu_a\to\nu_b} = \sin^{2}(2\theta)\,\sin^{2}\!\left(\frac{\Delta m^{2}c^{4}L}{4\hbar c E}\right) \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $\theta_C$ | Cherenkov cone angle of light from the charged secondary particle (e.g. electron or muon) a neutrino interaction produces, not the neutrino itself | rad |
| $n$ | refractive index of medium | 1 |
| $\beta$ | speed of that charged secondary particle / c | 1 |
| $\theta$ | mixing angle (two-flavour approx.) | rad |
| $\Delta m^{2}$ | difference of squared neutrino masses (quoted in eV²/c⁴) | kg² |
| $L$ | baseline distance | m |
| $E$ | neutrino energy | J |
| $\hbar$ | reduced Planck constant | J·s |
| $c$ | speed of light | m/s |
Sources
- Encyclopaedia Britannica — Neutrino
- Encyclopaedia Britannica — Cherenkov radiation
- NobelPrize.org — The Nobel Prize in Physics 1958 (Cherenkov, Frank, Tamm)
- Cowan, Reines et al. (1956) Detection of the Free Neutrino: a Confirmation, Science 124, 103
- NobelPrize.org — The Nobel Prize in Physics 1995 (Perl, Reines)
- Super-Kamiokande (1998) Evidence for Oscillation of Atmospheric Neutrinos, PRL 81, 1562
- SNO (2002) Direct Evidence for Neutrino Flavor Transformation, PRL 89, 011301
- NobelPrize.org — The Nobel Prize in Physics 2015 (neutrino oscillations)
- PDG 2024 review — Neutrino masses, mixing and oscillations
- NASA NSSDCA — Sun Fact Sheet (mass, central temperature; Earth comparison)
Crossovers
Neutrina Fade meets Nullwen (Upper Limit Statistics). Neutrina Fade's absolute mass is still unknown, but Nullwen's craft sets upper limits on it from experiments such as tritium beta decay.
Neutrina Fade meets Decay Dancer (Weak Nuclear Force / Beta Decay). Decay Dancer's beta decay seemed to lose energy until Pauli proposed a neutral particle in 1930. Neutrina Fade is that particle, carrying off the missing energy and momentum.
Neutrina Fade meets W-ZED (Weak Nuclear Force / Boson Carrier). Neutrina Fade's flavour changes mean neutrinos have mass. W-ZED's weak interactions are how they are produced and detected, each time in a definite flavour.
Wear the lore
- Neutrina Fade – Neutrino Ghost Matter Physics T-Shirt
- Related infographic poster: Three Neutrinos – Plate 054 Physics Poster
Concept keywords: Neutrino Ghost Matter, Neutrina Fade, Nuclear & Particle Physics, physics lore, Pixelated Physics