What is the frequency/wavelength of a neutrino?

Since energy and momentum are conserved, the neutrino has the energy and momentum that is the difference between the measured values for the parent and daughter particles, such as when a proton decays into a neutron and a positron. Neutrinos were first proposed as a possible explanation for missing energy and momentum in specific nuclear reactions, such as beta decay.

Neutrinos possess energy and momentum, which vary based on the reaction that produced them.

Given that a neutrino is a particle with momentum and energy, it can act like a particle or like a wave.

A neutrino's wavelength can range from a few hundredth of a meter to several meters. High momentum neutrinos have shorter wavelengths.

Neutrinos are generally associated with very high-energy phenomena such as nuclear reactions and cosmic events; however, they can have a wide range of energies, and therefore a wide range of frequencies and wavelengths. The precise frequency or wavelength of a neutrino would depend on its energy, which can vary significantly. Neutrinos have extremely small masses and interact very weakly with matter, making their detection difficult.