Planck-Scale Effects on Global Symmetries: Cosmology of Pseudo-Goldstone Bosons

We consider a minimal model where the Higgs boson arises as an elementary pseudo-Nambu-Goldstone boson. The model is based on an extended scalar sector with global SO(5)/SO(4) symmetry. To achieve the correct electroweak symmetry breaking pattern, the model is augmented either with an explicit symmetry breaking term or an extra singlet scalar field. We consider separately both of these possibili- ties. We fit the model with the known particle spectrum at the electroweak scale...

We build a mechanism of gravitational symmetry breaking (GSB) of a global U(1) symmetry based on the relaxation of the equivalence principle due to the mass variation of pseudo Nambu-Goldstone dark matter (DM) particles. This GSB process is described by the modified cosmological convergence mechanism of the Abnormally Weighting Energy (AWE) Hypothesis previously introduced by the authors. Several remarkable constraints from the Hubble diagram of far-away supernovae are derive...

We propose and study a scalar extension of the Standard Model which respects a $\mathbb{Z}_3$ symmetry remnant of the spontaneous breaking of a global $U(1)_\text{DM}$ symmetry. Consequently, this model has a natural dark matter candidate and a Goldstone boson in the physical spectrum. In addition, the Higgs boson properties are changed with respect to the Standard Model due to the mixing with a new particle. We explore regions in the parameter space taking into account bound...

We propose a pseudo-Nambu-Goldstone boson (pNGB) dark matter (DM) model based on an additional non-Abelian gauge symmetry $SU(2)_D$. The gauge symmetry $SU(2)_D$ is spontaneously broken to a global custodial symmetry $U(1)_V$ via the nonvanishing vacuum expectation values of $SU(2)_D$ doublet and triplet scalar fields. Due to the exact global symmetry $U(1)_V$, the lightest $U(1)_V$ charged particle becomes stable. We assume that the lightest charged particle in the model is ...

Scenarios where gravitinos with GeV masses make up dark matter are known to be in tension with high reheating temperatures, as required by e.g. thermal leptogenesis. This tension comes from the longevity of the NLSPs, which can destroy the successful predictions of the standard primordial nucleosynthesis. However, a small violation of matter parity can open new decay channels for the NLSP, avoiding the BBN problems, while being compatible with experimental cosmic-ray constrai...

A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark matter since the current severe limits of dark matter direct detection experiments are naturally evaded by its nature. We construct a model with pNGB dark matter based on a {\it gauged} $U(1)_{B-L}$ symmetry, where no ad-hoc global symmetry is assumed. The model keeps natural suppression mechanism for the dark matter direct detection cross section. On the other hand, the pNGB can decay through the new h...

Spontaneous Lorentz violation due to a time-dependent expectation value for a massless scalar has been suggested as a method for dynamically generating dark energy. A natural candidate for the scalar is a Goldstone boson arising from the spontaneous breaking of a U(1) symmetry. We investigate the low-energy effective action for such a Goldstone boson in a general class of models involving only scalars, proving that if the scalars have standard kinetic terms then at the {\em c...

We consider scale invariant models where the classical scale invariance is broken perturbatively by radiative corrections at the electroweak scale. These models offer an elegant and simple solution to the hierarchy problem. If we further require the cosmological constant to be small then such models are also highly predictive. Indeed, the minimal such model, comprising a Higgs doublet and a real singlet, has the same number of parameters as the standard model. Although this m...

Motivated by the absence of signals of new physics in both searches for new particles at LHC and for a Weakly Interacting Massive Particle (WIMP) dark matter candidate, we consider a scenario where supersymmetry is broken at a scale above the reheating temperature. The low energy particle content consists then only in Standard Model states and a gravitino. We investigate the possibility that the latter provides the main component of dark matter through a freeze in mechanism f...

Democracy among the same type of particles is a useful paradigm in studying masses and interactions of particles with supersymmetry(SUSY) or without SUSY. This simple idea predicts the presence of massless particles. We attempt to use one of these massless pseudoscalar particles as generating the cosmological dark energy(DE) potential. To achieve the extremely shallow potential of DE, the pseudoscalar boson is required not to couple to the QCD anomaly. So, we consider two pse...