TeV- and MeV-physics out of an $SU_{L}(2)\times U_{R}(1)_{J} \times U(1)_{K}$ model.

The standard electroweak interaction is here re-assessed to accommodate two different situations in Particle Physics. The first one is a $Z'$-model at the TeV-scale physics. The second one tackles the recent discussion of a possible fifth force mediated by a $17$-MeV X-boson associated with an electron-positron emission in the transition of an excited 8-Beryllium to its ground state. The anomaly-free model that provides these two scenarios is based on an $SU_{L}(2) \times U_{R}(1)_{J} \times U(1)_{K}$-symmetry. It yields a new massive neutral boson, an exotic massive neutral fermion, right-neutrinos and an additional neutral Higgs particle, which stems from a supplementary Higgs field, introduced along with the usual Higgs doublet responsible for the electroweak breaking and the masses of $W^{\pm}$ and $Z^{0}$. Yukawa interactions of the two scalars generate the masses of the Standard Model leptons, neutrinos and a new exotic fermion of the model. The vacuum expectation values of the Higgses fix up two independent energy scales. One of them is the well-confirmed electroweak scale, $246 \, \mbox{GeV}$, whereas the other one is set up by adopting an experimental estimate for the $Z'$-mass.