Mass Operator and Gauge Field Theory with Five-variable Field Functions

To investigate the mass generating problem without Higgs mechanism we present a model in which a new scalar gauge coupling is naturally introduced. Because of the existence of production and annihilation for particles in quantum field theory, we extend the number of independent variables from conventional four space-time dimensions to five ones in order to describe all degrees of freedom for field functions while the conventional space-time is still retained to be the background. The potential fifth variable is nothing but the proper time of particles. In response, a mass operator $(\hat{m}=-i\hbar \frac{\partial}{\partial\tau})$ should be introduced. After that, the lagrangian for free fermion fields in terms of five independent variables and mass operator is written down. By applying the gauge principle, three kinds of vector gauge couplings and one kind of scalar gauge coupling are naturally introduced. In the current scenario, the mass spectrum for all fundamental particles is accounted for in principle by solving the eigenvalue of mass operator under the function of all kinds of interactions. Moreover, there no any auxiliary mechanism including spontaneous symmetry breaking get involved in the model. Therefore, traditional problems in the standard model such as the vacuum energy problem are removed from our model, as well as the hierarchy problem on the mass spectrum for fundamental particles.