Conveners
Unification of Forces
- Volodymyr Takhistov
Unification of Forces
- Natsumi Nagata (University of Tokyo)
Contrary to SUSY-based GUT models, the gauge couplings in non-SUSY models do not unify naturally. However, gauge coupling unification may still be achieved by intermediate symmetry breaking steps or new physics around the TeV scale. Motivated by this, we perform fits to an SO(10)-based GUT model with one-step symmetry breaking to the SM. Neutrino masses are generated by the type-I or type-II...
Although SUSY is less natural than hoped, it is still able to explain several correlations beyond the standard model. A persistently appealing feature of supersymmetry is that it leads to gauge coupling unification, which suggests that the forces unify. For even minimal supersymmetric SU(5) unification, there are previously unexplored avenues. I will focus on the effect of pushing the...
A spontaneously broken hidden U(1)_h gauge symmetry can explain both the dark matter stability and the observed relic abundance. In this framework, the light gauge boson can mediate the strong dark matter self-interaction, which addresses astrophysical observations that are hard to explain in collisionless cold dark matter. Motivated by flavoured grand unified theories, we introduce...
The Grand Unified Theory (GUT) is a very interesting paradigm beyond the Standard Model. However, in simple GUT models, there are still missing pieces, such as neutrino masses, cosmological inflation, and a dark matter candidate. In this talk, I will discuss simple GUT models in which these missing pieces are supplemented.
Simple ways of implementing Peccei-Quinn (PQ) symmetry to solve the strong CP problem in renormalizable SUSYSO(10) models with a minimal Yukawa sector is suggested. Realistic fermion mass generation requires that a second pair of Higgs doublets survive down to the PQ-scale. How unification of gauge couplings can be achieved in this context is demonstrated. Higgsino mediated proton decay rate...
We present a Grand Unified Theory where the usual $E_6$ gauge coupling unification is supplemented by a local $SU(2)_F \times U(1)_F$ family symmetry. We discuss its origin inspiring our model by an embedding into $E_8$ which can be seen as an unifying force. We argue that the presence of such a family symmetry has remarkable implications for both high-scale and low scale physics: First,...
In natural GUT, most of problems in SUSY GUT can be solved under natural assumption in which all interactions including higher dimensional interactions
are introduced with O(1) coefficients. Interestingly, small deviation from
the complete natural GUT makes spontaneous SUSY breaking possible. We study the possibility that axino becomes the LSP in this scenario.
Precise measurements of the standard model parameters by the LEP has shown that supersymmetry realizes precise coupling unification. We introduce a non-supersymmetric scheme of coupling unification via the Higgs parity and show how precise unification is realized. We discuss the prediction on the proton decay rate and the importance of the precise measurement of the standard model parameters....
In the MSSM extended by a complete vectorlike family, precise top, bottom and tau Yukawa coupling unification can be achieved assuming SUSY threshold corrections which are typical for comparable superpartner masses. Furthermore, the unification is possible with a large unified coupling, implying that all three fermion masses can be simultaneously close to their IR fixed points. Assuming...
