Retrieving "Emission Absorption" from the archives

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1. Photons

   Linked via "emission/absorption"

   Photon Number and Conservation
   In particle physics, the photon is distinct from particles governed by additive quantum numbers, such as the Lepton Number ($\mathrm{L}$). Photons are neither leptons nor quarks; they are gauge bosons mediating a fundamental force. Consequently, the total number of photons in a [closed system](/entries/…