Left-right-symmetric model building
We have studied left-right-symmetric (LR) model building in two specific instances: the Minimal Left-Right-Symmetric Model (MLRM), with gauge group SU (3)C ⊗ SU (2)L ⊗ SU (2)R ⊗ U (1)B−L and parity as the LR symmetry; and a non-supersymmetric, trinified theory, with gauge structure SU (3)L ⊗ SU (3)R ⊗ SU (3)C ⊗ Z3 and an additional, novel, SU (3) family symmetry. For the MLRM, we have rederived the Lagrangian in the gauge and mass eigenbases, partly using the SARAH  model building framework. We have demonstrated how the gauge symmetry is broken to the Standard Model, and explicitly found the corresponding Goldstone bosons. For the trinified model, we have constructed the Lagrangian, spontaneously broken the gauge and global symmetries, and calculated the masses and charges of the resulting particle spectra. We show that the addition of the SU (3) family symmetry reduces the amount of free parameters to less than ten. We also demonstrate a possible choice of vacuum which breaks the trinified gauge group down to SU (3)C ⊗ U (1)Q , and find particularly simple minimum for this choice of potential. We conclude that the MLRM deserves its place as a popular LR extension, with several appealing features, such as naturally light neutrinos. The trinified model with SU (3) family symmetry, meanwhile, is an economic and exciting new theory. Our first, simple version seems phenomenologically viable, using very few parameters. Furthermore, several other theoretical variations are possible, many of which seem worthy of study.
LU TP 15-30