Decay Dancer: Weak Nuclear Force / Beta Decay
Nuclear & Particle Physics arc, page 172 of 193. Back to The Pixelated Physics Universe
Who they are
Inside some nuclei, a neutron quietly changes its identity. In beta-minus decay the weak force turns a neutron into a proton, emitting an electron and an antineutrino. Decay Dancer wears it in pixel art on a unisex tee.
Decay Dancer 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 free neutron decays into a proton, an electron and an antineutrino, because one down quark turns into an up quark by emitting a W boson. The small mass difference is released as energy shared by the decay products.
$$ \begin{gathered} n \to p + e^{-} + \bar\nu_e \\ d \to u + W^{-} \to u + e^{-} + \bar\nu_e \\ Q = \left(m_n - m_p - m_e\right)c^{2} \approx 0.782\ \text{MeV} \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $n, p$ | neutron, proton | — |
| $e^{-}$ | electron | — |
| $\bar\nu_e$ | electron antineutrino | — |
| $d, u$ | down, up quark | — |
| $W^{-}$ | virtual W boson | — |
| $m_n, m_p, m_e$ | neutron, proton, electron masses | kg |
| $Q$ | kinetic energy shared by the decay products (neutrino mass neglected; quoted in MeV) | J |
Sources
- NIST CODATA 2022 — neutron mass energy equivalent in MeV
- NIST CODATA 2022 — proton mass energy equivalent in MeV
- NIST CODATA 2022 — electron mass energy equivalent in MeV
- PDG 2024 listings — neutron (mean life 878.4 ± 0.5 s; beam vs bottle note)
- Wietfeldt & Greene (2011) Colloquium: The neutron lifetime, Rev. Mod. Phys. 83, 1173
- Encyclopaedia Britannica — Beta decay
- Encyclopaedia Britannica — Neutrino
- 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)
- Wu, Ambler, Hayward, Hoppes, Hudson (1957) Experimental Test of Parity Conservation in Beta Decay, Phys. Rev. 105, 1413
- NobelPrize.org — The Nobel Prize in Physics 1957 (Yang, Lee)
- Feynman Lectures on Physics Vol. I Ch. 52: Symmetry in Physical Laws
- PDG 2024 listings — W boson (mass world average and CDF tension)
- PDG 2024 review — Electroweak model and constraints on new physics
Crossovers
Decay Dancer meets W-ZED (Weak Nuclear Force / Boson Carrier). Decay Dancer turns a neutron into a proton. W-ZED carries the change: the W boson lets a down quark become an up quark, emitting an electron and an antineutrino.
Decay Dancer meets Neutrina Fade (Neutrino Ghost Matter). 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.
Decay Dancer meets Recoilwyn (Radioactive Recoil). Recoilwyn followed atoms recoiling from alpha decay. Decay Dancer's beta decay has a recoil too, and its energy spectrum was the clue that pointed to the neutrino.
Wear the lore
- Decay Dancer – Weak Nuclear Force / Beta Decay Physics T-Shirt
- Related infographic poster: Three Neutrinos – Plate 054 Physics Poster
Concept keywords: Weak Nuclear Force / Beta Decay, Decay Dancer, Nuclear & Particle Physics, physics lore, Pixelated Physics