Peccei-Quinn Symmetry Research Articles

Pecci-Quinn Extension of the Natural Hybrid Inflation Model

The hybrid inflation which combines the supersymmetric hybrid model and the natural inflation model, was proposed to achieve the spectral index of 0.96, and an axion decay constant of intermediate scale. By introducing both the U(1)R and a shift symmetry and employing the minimal K?hler potential, we were able to avoid the eta-problem. The two inflaton fields in this model can admit a large non-Gaussianity. For a full realization of the idea of the natural inflation, the shift symmetry in the model should be embedded in a U(1)PQ symmetry.

2 Higgs or not 2 Higgs

Motivated by recent results from the LHC experiments, we analyze Higgs couplings in two Higgs doublet models with an approximate PQ symmetry. Models of this kind can naturally accommodate sizable modifications to Higgs decay patterns while leaving production at hadron colliders untouched. Near the decoupling limit, we integrate out the heavy doublet to obtain the effective couplings of the SM-like Higgs and express these couplings in a physically transparent way, keeping all orders in (mh/mH) for small PQ breaking. Considering supersymmetric models, we show that the effects on the Higgs couplings are considerably constrained.

Significant neutrinoless double beta decay with quasi-Dirac neutrinos

A significant signal of neutrinoless double beta decay can be consistent with the existence of light quasi-Dirac neutrinos. To demonstrate this possibility, we consider a realistic model where the neutrino masses and the neutrinoless double beta decay can be simultaneously generated after a Peccei-Quinn symmetry breaking.

Light dark matter and the electroweak phase transition in the NMSSM

We analyze the stability of the vacuum and the electroweak phase transition in the NMSSM close to the Peccei-Quinn symmetry limit. This limit contains light Dark Matter (DM) particles with a mass significantly smaller than the weak scale and also light CP-even and CP-odd Higgs bosons. Such light particles lead to a consistent relic density and facilitate a large spin-independent direct DM detection cross section, that may accommodate the recently reported signatures at the DAMA and CoGeNT experiments. Studying the one-loop effective potential at finite temperature, we show that when the lightest CP-even Higgs mass is of the order of a few GeV, the electroweak phase transition tends to become first order and strong. The inverse relationship between the direct-detection cross-section and the lightest CP-even Higgs mass implies that a cross-section of the order of 10$^{-41}$ cm$^2$ is correlated with a strong first order phase transition.

Non-minimal Higgs inflation and non-thermal leptogenesis in a supersymmetric Pati-Salam model

We consider a supersymmetric (SUSY) Grand Unified Theory (GUT)based on the gauge group GPS = SU(4)C × SU(2)L × SU(2)R, which incorporates non-minimalchaotic inflation, driven by a quartic potential associated withthe Higgs fields involved in the spontaneous breaking of GPS.The inflationary model relies on renormalizable superpotentialterms and does not lead to overproduction of magnetic monopoles.It is largely independent of the one-loop radiative correctionsand can become consistent with the current observational data onthe inflationary observables, with the symmetry breaking scale ofGPS assuming its SUSY value. Within our model, the strongCP and the μ problems of the minimal SUSY standard model canbe resolved via a Peccei-Quinn symmetry. Moreover baryogenesisoccurs via non-thermal leptogenesis realized by theout-of-equilibrium decay of the right-handed neutrinos, which areproduced by the inflaton's decay. We consider two versions of sucha scenario, assuming that the inflaton decays to the lightest orto the next-to-lightest right-handed neutrino. Both scenaria canbecome compatible with the constraints arising from the baryonasymmetry of the universe, the gravitino limit on the reheatingtemperature and the upper bound on the light neutrino masses,provided that the gravitino is somehow heavy. In the secondscenario, extra restrictions from the SU(4)C GUT symmetryon the heaviest Dirac neutrino mass and the data on theatmospheric neutrino oscillations can be also met.

Two Higgs doublets from fermion condensation

We consider the most generic situation in models where the electroweak symmetry is broken by the condensation of a strongly coupled fermion sector, such as for instance a fourth generation. We study the scalar content resulting from the condensation of both the up and the down type fermions, corresponding to a two-Higgs doublet model. We estimate the scalar spectrum using the Nambu--Jona-Lasinio model, improved by the renormalization group. We show that the scalar spectrum is generically lighter than for the case with only one right-handed fermion condensing and that due to a remnant Peccei-Quinn symmetry the lightest state is the pseudo-scalar, with masses ranging typically from 10 GeV to 120 GeV. We discuss the phenomenological consequences of this distinct spectrum.

Updating the neutron electric dipole moment in a fourth generation standard model

A fourth generation of quarks, if it exist, may provide sufficient CP violation for the baryon asymmetry of the Universe. We estimate the neutron electric dipole moment in the presence of a fourth generation, and find it would be dominated by the strange quark chromoelectric dipole moment, assuming it does not get wiped out by a Peccei-Quinn symmetry. Both the three electroweak loop and the two-loop electroweak/one-loop gluonic contributions are considered. With m_{b'}, m_{t'} at 500 GeV or so that can be covered at the LHC, and with a Jarlskog CPV factor that is consistent with hints of New Physics in b to s transitions, the neutron EDM is found around 10^{-31}e cm, still far below the 10^{-28}e cm reach of the new experiments being planned or under construction.

Natural Peccei-Quinn symmetry in the 3-3-1 model with a minimal scalar sector

In the framework of a 3-3-1 model with a minimal scalar sector we make a detailed study concerning the implementation of the Peccei-Quinn symmetry in order to solve the strong $CP$ problem. For the original version of the model, with only two scalar triplets, we show that the entire Lagrangian is invariant under a Peccei-Quinn-like symmetry but no axion is produced since a $U(1)$ subgroup remains unbroken. Although in this case the strong $CP$ problem can still be solved, the solution is largely disfavored since three quark states are left massless to all orders in perturbation theory. The addition of a third scalar triplet removes the massless quark states but the resulting axion is visible. In order to become realistic the model must be extended to account for massive quarks and an invisible axion. We show that the addition of a scalar singlet together with a ${Z}_{N}$ discrete gauge symmetry can successfully accomplish these tasks and protect the axion field against quantum gravitational effects. To make sure that the protecting discrete gauge symmetry is anomaly-free we use a discrete version of the Green-Schwarz mechanism.

F-theory GUTs withU(1)symmetries: Generalities and survey

We study the structure of $SU(5)$ $F$-theory grand unified theory (GUT) models that engineer additional $U(1)$ symmetries. These are highly constrained by a set of relations observed by Dudas and Palti (DP) that originate from the physics of four-dimensional anomaly cancellation. Using the DP relations, we describe a general tension between unification and the suppression of dimension 5 proton decay when one or more $U(1)$'s are Peccei-Quinn (PQ) symmetries and hypercharge flux is used to break the $SU(5)$ GUT group. We then specialize to spectral cover models, whose global completions in $F$ theory we know how to construct. In that setting, we provide a technical derivation of the DP relations, construct spectral covers that yield all possible solutions to them, and provide a complete survey of spectral cover models for $SU(5)$ GUTs that exhibit two $U(1)$ symmetries.

Mitigating moduli messes in low-scale SUSY breaking

We discuss the physics of moduli (light scalar fields with Planck-suppressed couplings to matter) in the case of low-scale supersymmetry breaking such as gauge mediation. We argue that even if the mechanism of moduli stabilization is decoupled from the mechanism of SUSY breaking, moduli masses will generically be parametrically related to the gravitino mass once the cancellation of the cosmological constant is taken into account. For low- scale SUSY breaking, this implies that moduli fields are light, long-lived relics that will generically drive the universe into a matter-dominated phase, in contradiction to standard BBN. We discuss two scenarios for evading this problem. The first is to consider very tuned supergravity potentials that can make the moduli heavy enough to decay at early times and reheat above the temperature of BBN. Viable cosmology can be achieved in this scenario, which has a population of highly relativistic light gravitinos arising from decays of moduli. Next, we consider the more natural scenario with light moduli. The saxion field associated with the solution of the strong CP problem provides the most natural candidate for driving thermal inflation, which dilutes the moduli. We construct an explicit model for this scenario, when the PQ symmetry breaking scale is larger than the messenger scale. The combination of the constraints on relic abundance and gamma-ray flux from decay of the moduli favors a particular region of SUSY breaking scale, 2 x 10^3 - 10^4 TeV. For either scenario, we find that it is generic for low-scale SUSY to be associated with late entropy production and accompanying low reheating temperatures.

The μ problem and sneutrino inflation

We consider sneutrino inflation and post-inflation cosmology in the singlet extension of the MSSM with approximate Peccei-Quinn(PQ) symmetry, assuming that supersymmetry breaking is mediated by gauge interaction. The PQ symmetry is broken by the intermediate-scale VEVs of two flaton fields, which are determined by the interplay between radiative flaton soft masses and higher order terms. Then, from the flaton VEVs, we obtain the correct mu term and the right-handed(RH) neutrino masses for see-saw mechanism. We show that the RH sneutrino with non-minimal gravity coupling drives inflation, thanks to the same flaton coupling giving rise to the RH neutrino mass. After inflation, extra vector-like states, that are responsible for the radiative breaking of the PQ symmetry, results in thermal inflation with the flaton field, solving the gravitino problem caused by high reheating temperature. Our model predicts the spectral index to be n_s\simeq 0.96 due to the additional efoldings from thermal inflation. We show that a right dark matter abundance comes from the gravitino of 100 keV mass and a successful baryogenesis is possible via Affleck-Dine leptogenesis.

Axion model in gauge-mediated supersymmetry breaking and a solution to the μ/Bμ problem

We present a simple supersymmetric axion model that can naturally explain the origin of the Higgs mu and Bmu terms in gauge mediation while solving the strong CP problem. To stabilize the Peccei-Quinn scale, we consider mixing between the messenger fields that communicate the supersymmetry and Peccei-Quinn symmetry breaking to the visible sector. Such mixing leads to the radiative stabilization of the Peccei-Quinn scale. In the model, a Higgs coupling to the axion superfield generates the B parameter at the soft mass scale while a small mu term is induced after the Peccei-Quinn symmetry breaking. We also explore the phenomenological and cosmological aspects of the model, which crucially depend on the saxion and axino interactions with the ordinary particles induced by the Higgs coupling to the axion superfield.

Theμproblem and the axion in gauge mediation

We revisit the idea of generating the Higgs mu parameter through a spontaneously broken Peccei-Quinn (PQ) symmetry in gauge-mediated supersymmetry breaking scenario. For the messenger scale of gauge mediation higher than the PQ scale, the setup naturally generates mu ~ m_soft and the Higgs soft parameter B \leq O(m_soft) with the CP phase of B aligned to the phase of gaugino masses, while giving the PQ scale v_PQ ~ \surd (m_soft {\Lambda}), where m_soft denote the gauge-mediated gaugino or sfermion masses and {\Lambda} is the cutoff scale which can be identified as the Planck scale or the GUT scale. The PQ sector of the model results in distinctive cosmology including a late thermal inflation. We discuss the issue of dark matter and baryogenesis in the resulting thermal inflation scenario, and find that a right amount of gravitino dark matter can be produced together with a successful Affleck-Dine leptogenesis, when the gravitino mass m_{3/2} = O(100) keV.

Universal seesaw from left–right and Peccei–Quinn symmetry breaking

To generate the lepton and quark masses in the left–right symmetric models, we can consider a universal seesaw scenario by integrating out heavy fermion singlets which have the Yukawa couplings with the fermion and Higgs doublets. The universal seesaw scenario can also accommodate the leptogenesis with Majorana or Dirac neutrinos. We show that the fermion singlets can obtain their heavy masses from the Peccei–Quinn symmetry breaking.

Natural inflation and flavor mixing from Peccei–Quinn symmetry breaking

We propose a left–right symmetric model to simultaneously give natural inflation and flavor mixing from a Peccei–Quinn symmetry breaking at the Planck scale. Our model can be embedded into SO(10) grand unification theories.

Dark matter,μproblem, and neutrino mass with gaugedRsymmetry

We show that the mu problem and the strong CP problem can be resolved in the context of the gauged U(1)_R symmetry, realizing an automatic Peccei-Quinn symmetry. In this scheme, right-handed neutrinos can be introduced to explain small Majorana or Dirac neutrino mass. The U(1)_R D-term mediated SUSY breaking, called the U(1)_R mediation, gives rise to a specific form of the flavor-conserving superpartner masses. For the given solution to the mu problem, electroweak symmetry breaking condition requires the superpartners of the Standard Model at low energy to be much heavier than the gravitino. Thus dark matter candidate can be either gravitino or right-handed sneutrino. In the Majorana neutrino case, only gravitino is a natural dark matter candidate. On the other hand, in the Dirac neutrino case, the right-handed sneutrino can be also a dark matter candidate as it gets mass only from SUSY breaking. We discuss the non-thermal production of our dark matter candidates from the late decay of stau and find that the constraints from the Big Bang Nucleosynthesis can be evaded for a TeV-scale stau mass.

A solution of the strongCPproblem via the Peccei-Quinn mechanism through the Nieh-Yan modified gravity and cosmological implications

By identifying the recently introduced Barbero-Immirzi field with the QCD axion, the strong CP problem can be solved through the Peccei-Quinn mechanism. A specific energy scale for the Peccei-Quinn symmetry breaking is naturally predicted by this model. This provides a complete dynamical setting to evaluate the contribution of such an axion to the cold dark matter content of the Universe. Furthermore, a tight upper bound on the tensor-to-scalar ratio production of primordial gravitational waves can be fixed, representing a strong experimental test for this model.

Revealing Randall-Sundrum hidden valleys

We study 5D gauge symmetries in the Randall-Sundrum geometry that are hidden from the standard model through either small 5D gauge coupling, or through vanishing quantum numbers for the standard model fields. Geometric warping of 5D gravity creates a TeV-scale bridge from the standard model to the hidden sector gauge fields. We apply these concepts to a revival of the electroweak axion model, in which the dynamics of Peccei-Quinn symmetry breaking occur at the TeV scale.

Axion protection from flavor

The QCD axion fails to solve the strong CP problem unless all explicit PQ violating, Planck-suppressed, dimension n < 10 operators are forbidden or have exponentially small coefficients. We show that all theories with a QCD axion contain an irreducible source of explicit PQ violation which is proportional to the determinant of the Yukawa interaction matrix of colored fermions. Generically, this contribution is of low operator dimension and will drastically destabilize the axion potential, so its suppression is a necessary condition for solving the strong CP problem. We propose a mechanism whereby the PQ symmetry is kept exact up to n = 12 with the help of the very same flavor symmetries which generate the hierarchical quark masses and mixings of the SM. This “axion flavor protection” is straightforwardly realized in theories which employ radiative fermion mass generation and grand unification. A universal feature of this construction is that the heavy quark Yukawa couplings are generated at the PQ breaking scale.

ON QUANTUM SPECIAL KÄHLER GEOMETRY

We compute the effective black hole potential V BH of the most general [Formula: see text], d = 4 (local) special Kähler geometry with quantum perturbative corrections, consistent with axion-shift Peccei–Quinn symmetry and with cubic leading order behavior. We determine the charge configurations supporting axion-free attractors, and explain the differences among various configurations in relations to the presence of "flat" directions of V BH at its critical points. Furthermore, we elucidate the role of the sectional curvature at the nonsupersymmetric critical points of V BH , and compute the Riemann tensor (and related quantities), as well as the so-called E-tensor. The latter expresses the nonsymmetricity of the considered quantum perturbative special Kähler geometry.