In an old episode ("Mars University") of Futurama which is a TV show, a character named Professor Farnsworth was trying to lecture "Superdupersymmetric String Theory" and "Witten's Dog" to some other characters.
He wrote on board a Feynman diagram, the equation under the diagram looks very much like the electron capture mechanism: $p + e^- \rightarrow n + \nu_e$, except for that wavy underline. However, the Feynman diagram above does not look like the electron capture? Also is there any reference to that caption:"Neutron encrusted steaming hot dark matter"?
Wikipedia said that the bottom equation resembles an equation that constrains the mass density of neutrinos in the universe, I wonder if there is any reference to this equation.