The large hierarchy between the Planck scale and the weak scale can be explained by the dynamical breaking of supersymmetry in strongly coupled gauge theories. Similarly, the hierarchy between the ...Planck scale and the energy scale of inflation may also originate from strong dynamics, which dynamically generate the inflaton potential. We present a model of the hidden sector which unifies these two ideas, i.e., in which the scales of inflation and supersymmetry breaking are provided by the dynamics of the same gauge group. The resultant inflation model is chaotic inflation with a fractional power-law potential in accord with the upper bound on the tensor-to-scalar ratio. The supersymmetry breaking scale can be much smaller than the inflation scale, so that the solution to the large hierarchy problem of the weak scale remains intact. As an intrinsic feature of our model, we find that the sgoldstino, which might disturb the inflationary dynamics, is automatically stabilized during inflation by dynamically generated corrections in the strongly coupled sector. This renders our model a field-theoretical realization of what is sometimes referred to as sgoldstino-less inflation.
The observation of the B-mode in the cosmic microwave background radiation combined with the so-called Lyth bound suggests the trans-Planckian variation of the inflaton field during inflation. Such a ...large variation generates concerns over inflation models in terms of the effective field theory below the Planck scale. If the inflaton resides in a Riemann surface and the inflaton potential is a multivalued function of the inflaton field when it is viewed as a function on a complex plane, the Lyth bound can be satisfied while keeping field values in the effective field theory within the Planck scale. We show that a multivalued inflaton potential can be realized starting from a single-valued Lagrangian of the effective field theory below the Planck scale.
Similarities between the gauge meditation of supersymmetry breaking and the QCD axion model suggest that they originate from the same dynamics. We present a class of models where supersymmetry and ...the Peccei–Quinn symmetry are simultaneously broken. The messengers that mediate the effects of these symmetry breakings to the Standard Model are identical. Since the axion resides in the supersymmetry breaking sector, the saxion and the axino are heavy. We show constraints on the axion decay constant and the gravitino mass.
Axion cold dark matter from standard misalignment typically requires a decay constant fa≳1011 GeV . Kinetic misalignment and parametric resonance easily allow lower values of fa when the radial ...Peccei-Quinn (PQ) symmetry breaking field takes large initial values. Here, we consider the effects of inflation on kinetic misalignment and parametric resonance. We assume that the initial PQ field value is determined by quantum fluctuations, and is set by the Hubble parameter during inflation, HI, and the PQ field mass. PQ field oscillations begin before or after the completion of reheating after inflation at a temperature TR. We determine the range of fa and the inflationary parameters (HI,TR) consistent with axion dark matter for a quartic potential for the PQ field. We find that 108 GeV <fa<1011 GeV can consistently produce axion dark matter. A significant portion of the allowed parameter space predicts rare kaon decays, KL→(π0+missingenergy), and/or suppression of structure formation on small scales.
In recent years, there has been controversy concerning the anomaly-mediated gaugino mass in the superspace formalism of supergravity. In this paper, we reexamine the gaugino mass term in this ...formalism by paying particular attention to the symmetry that controls gaugino masses in supergravity. We first discuss super-diffeomorphism invariance of path-integral measures of charged superfields. As we will show, the super-diffeomorphism-invariant measure is not invariant under a super-Weyl transformation, which is the origin of the anomaly-mediated gaugino mass. We show how the anomaly-mediated gaugino mass is expressed as a local operator in a Wilsonian effective action in a super-diffeomorphism-covariant way. We also obtain a gaugino mass term independent of the gauge choice of the fictitious super-Weyl symmetry in the super-Weyl compensator formalism, which reproduces the widely accepted result. We also discuss how to reconcile the gaugino mass term in the local Wilsonian effective action and the gaugino mass term appearing in a nonlocal one-particle irreducible quantum effective action.
A
bstract
Supersymmetric Twin Higgs models ameliorate the fine-tuning of the electroweak scale originating from the heavy scalar top partners required by the non-discovery of them at the Large Hadron ...Collider. If the Lightest Supersymmetric Particle resides in the twin sector, it may play the role of dark matter even if it is charged under twin gauge interactions. We show that the twin stau is a viable candidate for charged dark matter, even if the twin electromagnetic gauge symmetry is unbroken, with thermal relic abundance that naturally matches the observed dark matter abundance. A wide parameter space satisfies all the experimental constraints including those on dark matter self-interactions. Twin stau dark matter can be observed in future direct detection experiments such as LUX-ZEPLIN. The stau has a mass in the range of 300–500 GeV, and in the minimal scenario, has a decay length long enough to be observed as a disappearing track or a long-lived particle at the Large Hadron Collider.
A
bstract
We discuss a simple model of thermal relic dark matter whose mass can be much larger than the so-called unitarity limit on the mass of point-like particle dark matter. The model consists of ...new strong dynamics with one flavor of fermions in the fundamental representation which is much heavier than the dynamical scale of the new strong dynamics. Dark matter is identified with the lightest baryonic hadron of the new dynamics. The baryonic hadrons annihilate into the mesonic hadrons of the new strong dynamics when they have large radii. Resultantly, thermal relic dark matter with a mass in the PeV range is possible.
We consider a scenario where supersymmetry breaking, its mediation, and the cancellation of the theta parameter of SU(3)C are all caused by a single chiral multiplet. The string axion multiplet is a ...natural candidate of such a superfield. We show that the scenario provides a convincing basis of focus point gaugino mediation, where the electroweak scale is explained with a moderate tuning among the parameters of the theory.
A
bstract
It is pointed out that in supersymmetric models with a new gauge symmetry under which the Higgs is charged, the fine-tuning of the electroweak symmetry breaking is relaxed due to ...suppression of the top Yukawa coupling at higher scales by a new large gauge coupling. We calculate the fine-tuning in an explicit model and find that the lower bounds on stops and gluino masses from the naturalness criterion are increased by several hundred GeV in comparison to the Minimal Supersymmetric Standard Model (MSSM). The fine-tuning is improved by one to two orders of magnitude as compared to the MSSM, as a consequence of both the suppression of the top Yukawa coupling and the additional tree-level contribution to the Higgs mass allowing for much lighter stops.
A
bstract
We study the simplest theories with exact spacetime parity that solve the strong CP problem and successfully generate the cosmological baryon asymmetry via decays of right-handed neutrinos. ...Lower bounds are derived for the masses of the right-handed neutrinos and for the scale of spontaneous parity breaking,
v
R
. For generic thermal leptogenesis,
v
R
≳ 10
12
GeV, unless the small observed neutrino masses arise from fine-tuning. We compute
v
R
in terms of the top quark mass, the QCD coupling, and the Higgs boson mass and find this bound is consistent with current data at 1
σ
. Future precision measurements of these parameters may provide support for the theory or, if
v
R
is determined to be below 10
12
GeV, force modifications. However, modified cosmologies do not easily allow reductions in
v
R
— no reduction is possible if leptogenesis occurs in the collisions of domain walls formed at parity breaking, and at most a factor 10 reduction is possible with non-thermal leptogenesis. Standard Model parameters that yield low values for
v
R
can only be accommodated by having a high degree of degeneracy among the right-handed neutrinos involved in leptogenesis. If future precision measurements determine
v
R
to be above 10
12
GeV, it is likely that higher-dimensional operators of the theory will yield a neutron electric dipole moment accessible to ongoing experiments. This is especially true in a simple UV completion of the neutrino sector, involving gauge singlet fermions, where the bound from successful leptogenesis is strengthened to
v
R
≳ 10
13
GeV.
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