Derivation on Physical Mechanism of Photons Without Intrinsic Momentum

In existing physical systems, the photon equivalent momentum model is generally adopted to explain optomechanical phenomena such as light pressure and laser cooling of atoms. The formula p=E/c defines the equivalent momentum of photons, and the mechanical interaction between light and matter is attributed to particle momentum exchange. To maintain theoretical selfconsistency, traditional systems artificially distinguish rest mass from equivalent mass, as well as real momentum from equivalent momentum. A large number of additional conceptual patches are applied to cover underlying logical contradictions, which causes confusion in fundamental physical definitions. This paper establishes a brandnew physical mechanism. Freely propagating photons only carry directional energy and possess neither intrinsic momentum nor equivalent momentum. The mechanical effect of photons occurs entirely at the instant of being absorbed by matter. The directional energy of photons converts into additional mass of matter and inherits the original propagation direction and speed of light of photons, thus generating real momentum conforming to classical definitions. Macroscopic light pressure is the superposition of two effects: directional momentum effect and intensified jitter of particles after energy absorption. Theoretical derivation and numerical calculation show that the model proposed in this paper is fully consistent with experimental data of light pressure, cold atom deceleration and cold atom acceleration. Compared with conceptual fragmentation in traditional theories, this paper adopts unified basic definitions of mass, energy and momentum throughout the text without artificial assumptions. The mechanism is concise and logically selfconsistent, fundamentally resolving longstanding physical contradictions concerning mechanical properties of photons.