Conveners
Parallel 3
- Alejandro Ibarra (Technical University of Munich)
The so called 331-models are SM extensions based on $SU(3)_c\times SU(3)_L\times U(1)_X$-gauge group. The scalar potential of 331-models is typically quite complicated, due to presence of three scalar triplets.
Although the 331 models have been extensively studied, the existence of multiple minima and metastability of the 331 scalar potential has not been studied in great detail in the...
In models with multiple Higgs doublets that trigger spontaneous electroweak symmetry breaking, one expects that the abundance of dimensionful quadratic couplings in the scalar potential allows for a regime where, apart from the would-be Goldstone bosons and a neutral Higgs-like state, all new scalars can have masses much larger than the electroweak scale. For models where CP invariance holds...
Pseudo Nambu-Goldstone (pNG) bosons can play important roles in particle physics, such as being a light dark matter (DM), the QCD axion to solve the strong CP problem, and so on. I point out that such a pNG boson is naturally realized by the finite modular symmetry, which may originate from the geometry of extra dimensions in the superstring models. An accidental global U(1) symmetry arises...
We show how to apply Lie symmetry analysis of partial differential equations (PDEs) to the Euler-Lagrange equations of multi-Higgs models, to determine their scalar Lie point symmetries. A Lie point symmetry is a structure-preserving transformation of the spacetime variables and the fields of the model, which is also continuous and connected to the identity. The Lie point symmetries can be...
In QFT, a metastable vacuum state can decay through quantum tunnelling. The calculation of the decay rate relies on instantons — a kind of non-trivial classical solution in the Euclideanized theory. However, sometimes theories with metastable vacua do not have any instanton solutions, thus rendering the usual method of calculating decay rates unusable. An important example of such a theory is...
We present a systematic study of one-loop quantum corrections in scalar effective field theories from a geometric viewpoint, emphasizing the role of field-space curvature and its renormalisation. By treating the scalar fields as coordinates on a Riemannian manifold, we exploit field redefinition invariance to maintain manifest coordinate independence of physical observables. Focusing on the...
We consider the extension of the Standard Model with an inert scalar doublet, three right-handed neutrinos, and singlet scalar fields, $\varphi$ and $S$. In this model, neutrino masses are zero in the limit of the unbroken $Z_4$ discrete symmetry. We show that when the singlet scalar field $\varphi$ gets a VEV, the $Z_4$ symmetry is broken to $Z_2$, and neutrino masses are generated at...
I'll present a variant of the Three-Higgs-Doublet Model (3HDM), referred to as the BGL-3HDM, which incorporates a $U(1)_1\times U(1)_2$ symmetry that leads to a 'horizontal' Yukawa structure, where a particular doublet is the primary source of mass for a particular fermion generation. In the version considered here, the Yukawa matrices in the down-quark and charged-lepton sectors are...
