Physical Essence Analysis of the Nineteen Free Parameters in the Standard Model

The Standard Model of particle physics contains nineteen independent free input parameters. For more than a hundred years, researchers generally regard these fundamental constants as preset values of the universe which can only be obtained by experimental measurement and cannot be derived from underlying physical laws. This forms a major theoretical difficulty in contemporary fundamental physics. This paper sorts out the underlying logic of microscopic matter and interaction based on the complete axiom system of the Photon Origin Theory. The core viewpoint is that the only stable structures that can sustain and build the steady state material world are protons and electrons. Neutrons are secondary composite structures formed by protons and electrons. Some concepts and matching parameters in the framework of the Standard Model correspond to transient particles with extremely short service time and cannot serve as basic units for constructing stable matter. Others are fitting assumptions artificially constructed within the theoretical framework and have no corresponding physical entities in the physical picture of this paper. Therefore they are not included in the source tracing research of the steady state system. This paper only discusses physical quantities whose mechanism can be explained within the steady state system. The fine structure constant is independent of the confinement energy ratio of protons and electrons. It cannot be derived relying on the locking configuration of protons and electrons and can only adopt experimentally measured values. The only fundamental question worth exploring is this. Among countless collision and locking configurations of photons, only protons and electrons can achieve stable locking and long term existence. All other high energy transient structures cannot maintain stable existence. The energy composition of neutrons belongs to a derivative effect of composite structures and its mechanism can be reasonably explained under this framework. This paper sorts out nine groups of parameters in the Standard Model, clarifies the quantity of parameters in each group, and covers nineteen free parameters in total. It lists mainstream reference values and classification judgments. It discusses physical quantities belonging to the steady state material system with interpretable mechanisms. For parameters corresponding only to transient particles or hypothetical constructions of the theoretical framework, it explains the reasons for excluding them from the research scope. For energy effects traditionally classified as weak interaction, a new mechanism interpretation is given. The weak force is not regarded as an independent fundamental interaction.