Electron capture results in the emission of which particle?

Electron capture results in the emission of which particle?

• A. Photon
• B. Electron
• C. Proton
• D. Neutrino

Answer: (D)

Electron capture is a weak-interaction process where a proton in the nucleus grabs an inner-shell electron and becomes a neutron, emitting an electron neutrino in the process. This neutrino carries away the energy released and balances lepton number, since the captured electron contributes +1 lepton number and the neutrino carries +1 as well. The capture typically creates a vacancy in the electron cloud that can lead to X-ray or Auger-electron emission afterward, but the particle emitted directly from the capture event is the neutrino. A photon or proton isn’t emitted in this primary reaction, and the nucleus actually loses a proton (becomes more neutron-rich), not gain one.

Electron capture is a weak-interaction process where a proton in the nucleus grabs an inner-shell electron and becomes a neutron, emitting an electron neutrino in the process. This neutrino carries away the energy released and balances lepton number, since the captured electron contributes +1 lepton number and the neutrino carries +1 as well. The capture typically creates a vacancy in the electron cloud that can lead to X-ray or Auger-electron emission afterward, but the particle emitted directly from the capture event is the neutrino. A photon or proton isn’t emitted in this primary reaction, and the nucleus actually loses a proton (becomes more neutron-rich), not gain one.