No, protons, neutrons, or nuclei themselves do not directly produce light in nuclear reactions like alpha decay. The emission of light or electromagnetic radiation, such as visible light or gamma rays, typically occurs as a result of transitions or interactions involving charged particles, such as electrons or ions.
In alpha decay, a radioactive nucleus emits an alpha particle, which consists of two protons and two neutrons. During this process, the parent nucleus undergoes a transformation and is converted into a different nucleus, releasing energy in the form of the alpha particle. However, the emission of the alpha particle itself does not involve the production of light.
That being said, the resulting daughter nucleus from the alpha decay may be in an excited state. Excited nuclei can transition to lower energy states by emitting photons, which are particles of light. These emitted photons can include gamma rays, which are high-energy photons, among other types of electromagnetic radiation. These photons are the ones that carry information about the nuclear reactions and can be detected as light.
So while the alpha particle itself does not produce light, subsequent processes involving the daughter nucleus, such as its de-excitation or interactions with other particles, can lead to the emission of electromagnetic radiation, including light.