Low scale unification of gauge interactions

We investigate the possibility of realizing the unification of the Standard Model gauge interactions at the low scale in four dimensions. We find that the fields needed to define a minimal theory where baryon and lepton numbers are local symmetries allow for unification at the low scale in agreement with experiments. In these scenarios the proton is stable and we briefly discuss the implications for cosmology.

Figure 1

Evolution of the gauge couplings in the Standard Model represented by dashed lines and in the new model where the unification scale is realized at $10^4\mathrm{TeV}$ (see the text for details).

Figure 2

Evolution of the gauge couplings with lepto-baryons where the unification scale is $M_U\sim 2\times 10^4\mathrm{TeV}$. Here we assume for simplicity $k_B=k_L=k_1$ for the running of the ${\alpha }_B$ and ${\alpha }_L$. At the $M_Z$ scale we find ${\alpha }_B^{-1}(M_Z)=25.17$ and ${\alpha }_L^{-1}(M_Z)=28.69$.