At first, it sounds like an anti-neutrino can "spontaneously" emit a positron to form a W boson, instead of finding an electron.
On re-reading, it's like the neutrino "bumps" the positive charge out of the proton. Like the neutrino interacting with a down quark will convert them into an up quark and a positron.
Edit: Inverse beta decay, commonly abbreviated to IBD, is a nuclear reaction involving electron antineutrino scattering off a proton, creating a positron and a neutron.
... The IBD reaction can only be initiated when the antineutrino possesses at least 1.806 MeV of kinetic energy (called the threshold energy). This threshold energy is due to a difference in mass between the products ( positron and neutrino ) and the reactants ( antineutrino and proton ) and also slightly due to a relativistic mass effect on the antineutrino. Most of the antineutrino energy is distributed to the positron due to its small mass relative to the neutron.
To state the obvious, since the Neutrino is massless, its energy can only come from momentum. Hence the distribution of the 1.806 MeV from the Wiki article above:
On re-reading, it's like the neutrino "bumps" the positive charge out of the proton. Like the neutrino interacting with a down quark will convert them into an up quark and a positron.
Edit: Inverse beta decay, commonly abbreviated to IBD, is a nuclear reaction involving electron antineutrino scattering off a proton, creating a positron and a neutron.
... The IBD reaction can only be initiated when the antineutrino possesses at least 1.806 MeV of kinetic energy (called the threshold energy). This threshold energy is due to a difference in mass between the products ( positron and neutrino ) and the reactants ( antineutrino and proton ) and also slightly due to a relativistic mass effect on the antineutrino. Most of the antineutrino energy is distributed to the positron due to its small mass relative to the neutron.
https://en.wikipedia.org/wiki/Inverse_beta_decay
To state the obvious, since the Neutrino is massless, its energy can only come from momentum. Hence the distribution of the 1.806 MeV from the Wiki article above: