  A novel theory of the structure of elementary particles is outlined. The
proposed relativistic covariant space-time approach supposes that all massive
particles are composite particles formed by massless elementary particles with
opposite four-dimensional (4D) helicity. The attraction between two basic
particles originates from their mutual 4D density, which depends only on their
4D distance. The approach enables a consistent description of the internal
structure of massive elementary particles including the origin of their spin,
their mass, and the sign of their charge. The 4D rotational Hamiltonian depends
on the hyper-symmetric potential obtained by using the mutual density for the
source term of the 4D Poisson equation. The rotational eigenfunctions depend on
the 4D radius and on three angles, one of which is imaginary. This angle
accounts for the rotation of the time-like axis with respect to the
three-dimensional subspace representing a Lorentz transformation. We obtain the
wave equation of the basic particles by supposing that they are propagating
with the speed of light. Such subatomic massless particles are photons,
basic-quarks, and neutrinos, which we assume to be massless if they are free.
The results of the analytical calculations show that massive particles can only
be stable if the potential is a 4D well trapping the constituents. As a result,
we do not need the Higgs field for explaining the origin of the mass. In
particular, we show that electrons and positrons are such two-component systems
each consisting of two photons. The eigenvalue of the 4D rotational energy
determines the mass of the composite particle. We prove the relevance of the
novel theory by revisiting the hydrogen atom. The resulting energy eigenvalues
depend on three quantum numbers having no degenerated energy states. In
particular, it provides the Lamb shift.
