scholarly journals Gravitational waves from fundamental axion dynamics

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Anish Ghoshal ◽  
Alberto Salvio
Keyword(s):  
Phase Transition ◽  
Symmetry Breaking ◽  
Gravitational Waves ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
Energy Limit ◽  
The Masses ◽  
Infinite Energy ◽  
Independent Parameters ◽  
Breaking Scale

Abstract A totally asymptotically free QCD axion model, where all couplings flow to zero in the infinite energy limit, was recently formulated. A very interesting feature of this fundamental theory is the ability to predict some low-energy observables, like the masses of the extra fermions and scalars. Here we find and investigate a region of the parameter space where the Peccei-Quinn (PQ) symmetry is broken quantum mechanically through the Coleman-Weinberg mechanism. This results in an even more predictive framework: the axion sector features only two independent parameters (the PQ symmetry breaking scale and the QCD gauge coupling). In particular, we show that the PQ phase transition is strongly first order and can produce gravitational waves within the reach of future detectors. The predictivity of the model leads to a rigid dependence of the phase transition (like its duration and the nucleation temperature) and the gravitational wave spectrum on the PQ symmetry breaking scale and the QCD gauge coupling.

scholarly journals Primordial monopoles and strings, inflation, and gravity waves

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Joydeep Chakrabortty ◽  
George Lazarides ◽  
Rinku Maji ◽  
Qaisar Shafi
Keyword(s):  
Symmetry Breaking ◽  
Gravity Waves ◽  
Cosmic Strings ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
String Tension ◽  
Magnetic Monopoles ◽  
Intermediate Scale ◽  
Tension Parameter ◽  
The Universe

Abstract We consider magnetic monopoles and strings that appear in non-supersymmetric SO(10) and E6 grand unified models paying attention to gauge coupling unification and proton decay in a variety of symmetry breaking schemes. The dimensionless string tension parameter Gμ spans the range 10−6− 10−30, where G is Newton’s constant and μ is the string tension. We show how intermediate scale monopoles with mass ∼ 1013− 1014 GeV and flux ≲ 2.8 × 10−16 cm−2s−1sr−1, and cosmic strings with Gμ ∼ 10−11− 10−10 survive inflation and are present in the universe at an observable level. We estimate the gravity wave spectrum emitted from cosmic strings taking into account inflation driven by a Coleman-Weinberg potential. The tensor-to-scalar ratio r lies between 0.06 and 0.003 depending on the details of the inflationary scenario.

scholarly journals Realizing unification in two different SO(10) models with one intermediate breaking scale

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Tommy Ohlsson ◽  
Marcus Pernow ◽  
Erik Sönnerlind
Keyword(s):  
Gauge Coupling ◽  
Scalar Fields ◽  
Matching Conditions ◽  
Proton Lifetime ◽  
The Masses ◽  
Breaking Scale

AbstractWe derive the threshold corrections in $$\text {SO}(10)$$ SO ( 10 ) grand unified models with the intermediate symmetry being flipped $$\,\text {SU}(5)\times \text {U}(1)$$ SU ( 5 ) × U ( 1 ) or $$\,\text {SU}(3)\times \,\text {SU}(2)\times \text {U}(1)\times \text {U}(1)$$ SU ( 3 ) × SU ( 2 ) × U ( 1 ) × U ( 1 ) , with the masses of the scalar fields set by the survival hypothesis. These models do not achieve gauge coupling unification if the matching conditions do not take threshold corrections into account. We present results showing the required size of threshold corrections for any value of the intermediate and unification scales. In particular, our results demonstrate that both of these models are disfavored since they require large threshold corrections to allow for unification with a predicted proton lifetime above current experimental bounds.

Cosmic parity violation due to a flavor-space locked gauge field

2016 ◽  
Vol 25 (11) ◽  
pp. 1640011 ◽  
Author(s):  
Robert Caldwell
Keyword(s):  
Gravitational Waves ◽  
Gauge Field ◽  
Parity Violation ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
Line Of Sight ◽  
Microwave Background ◽  
Photon Polarization ◽  
Chiral Asymmetry ◽  
Cosmological Scenario

A flavor-space locked gauge field is shown to behave like a birefringent medium, imparting a preferred left- or right-circular polarization onto gravitational waves. In a cosmological scenario, such a gauge field can cause a primordial spectrum of gravitational waves to develop a net handedness. The degree of chiral asymmetry depends on the wavelength, the abundance of the gauge field, and the strength of the gauge coupling. An asymmetry in the gravitational wave spectrum would be imprinted on the photon polarization pattern of the cosmic microwave background at last scattering. In this scenario, cosmic parity violation is written on the sky, as we predict nonzero correlation of the curl polarization with the temperature, as well as curl with gradient polarization. We compare this phenomena with parity violation in models of chiral gravity, in which the chiral asymmetry is primordial, and with models of quintessence cosmic birefringence, in which parity-violating correlations are induced along the line of sight.

Exploring fundamental physics with gravitational waves

2017 ◽  
Vol 32 (28n29) ◽  
pp. 1744001
Author(s):  
Archil Kobakhidze
Keyword(s):  
Phase Transition ◽  
Symmetry Breaking ◽  
Gravitational Waves ◽  
Higgs Mechanism ◽  
Electroweak Symmetry Breaking ◽  
Noncommutative Space ◽  
Electroweak Symmetry ◽  
Fundamental Physics ◽  
Gravitational Wave Background ◽  
Shed Light

The direct discovery of gravitational waves opens of new avenues for exploring fundamental microscopic physics. In this presentation, a I will illustrate this by obtaining the stringent bounds on the scale of quantum fuzziness of hypothetical noncommutative space–time. I also discuss how future observations of stochastic gravitational wave background can shed light on the nature of the Higgs mechanism of the electroweak symmetry breaking and the related cosmological phase transition. a Based on a talk presented at the Conference on Cosmology, Gravitational Waves and Particles, NTU, Singapore, 6–10 February 2017.

scholarly journals Causal gravitational waves as a probe of free streaming particles and the expansion of the Universe

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Anson Hook ◽  
Gustavo Marques-Tavares ◽  
Davide Racco
Keyword(s):  
Phase Transition ◽  
Gravitational Waves ◽  
Gravity Waves ◽  
Wave Spectrum ◽  
Spectral Feature ◽  
Low Frequency ◽  
Low Frequencies ◽  
Expansion Of The Universe ◽  
The Difference ◽  
The Universe

Abstract The low frequency part of the gravitational wave spectrum generated by local physics, such as a phase transition or parametric resonance, is largely fixed by causality, offering a clean window into the early Universe. In this work, this low frequency end of the spectrum is analyzed with an emphasis on a physical understanding, such as the suppressed production of gravitational waves due to the excitation of an over-damped harmonic oscillator and their enhancement due to being frozen out while outside the horizon. Due to the difference between sub-horizon and super-horizon physics, it is inevitable that there will be a distinct spectral feature that could allow for the direct measurement of the conformal Hubble rate at which the phase transition occurred. As an example, free-streaming particles (such as the gravity waves themselves) present during the phase transition affect the production of super-horizon modes. This leads to a steeper decrease in the spectrum at low frequencies as compared to the well-known causal k3 super-horizon scaling of stochastic gravity waves. If a sizable fraction of the energy density is in free-streaming particles, they even lead to the appearance of oscillatory features in the spectrum. If the universe was not radiation dominated when the waves were generated, a similar feature also occurs at the transition between sub-horizon to super-horizon causality. These features are used to show surprising consequences, such as the fact that a period of matter domination following the production of gravity waves actually increases their power spectrum at low frequencies.

scholarly journals Threshold effects in SO(10) models with one intermediate breaking scale

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Davide Meloni ◽  
Tommy Ohlsson ◽  
Marcus Pernow
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Particle Physics ◽  
Gauge Coupling ◽  
Grand Unification ◽  
Threshold Effects ◽  
The Standard Model ◽  
Proton Lifetime ◽  
Supersymmetric Theories ◽  
Breaking Scale

AbstractDespite the successes of the Standard Model of particle physics, it is known to suffer from a number of deficiencies. Several of these can be addressed within non-supersymmetric theories of grand unification based on $$\text {SO}(10)$$ SO ( 10 ) . However, achieving gauge coupling unification in such theories is known to require additional physics below the unification scale, such as symmetry breaking in multiple steps. Many such models are disfavored due to bounds on the proton lifetime. Corrections arising from threshold effects can, however, modify these conclusions. We analyze all seven relevant breaking chains with one intermediate symmetry breaking scale, assuming the “survival hypothesis” for the scalar masses. Two are allowed by proton lifetime and two are disfavored by a failure to unify the gauge couplings. The remaining three unify at a too low scale, but can be salvaged by various amounts of threshold corrections. We parametrize this and thereby rank the models by the size of the threshold corrections required to save them.

FERMIONIC CONDENSATES IN SUPERSYMMETRIC COMPOSITE MODELS

1986 ◽  
Vol 01 (05) ◽  
pp. 355-363
Author(s):  
LEAH MIZRACHI
Keyword(s):  
Gauge Symmetry ◽  
Symmetry Breaking ◽  
Composite Model ◽  
Dynamical Mechanism ◽  
Model Based ◽  
Fermi Interaction ◽  
Composite Models ◽  
The Masses ◽  
Breaking Scale

Fermionic condensates are calculated in a background of instantons in a supersymmetric composite model based upon SU(2) hypercolor symmetry. Due to the effective 4-fermi interaction of the composites, the quasi-Goldstone fermion acquires a mass which is much smaller than ΛHC provided the gauge symmetry breaking scale, υ, is large enough for the approximation to be valid. (Typically υ≃eΛHC.) This provides a dynamical mechanism for generating the masses of quarks and leptons in this class of models.

scholarly journals Gravitational wave signals of dark matter freeze-out

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Danny Marfatia ◽  
Po-Yan Tseng
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
First Order ◽  
Stochastic Background ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
First Order Phase ◽  
Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

scholarly journals DYNAMICAL SYMMETRY BREAKING IN A MINIMAL 3-3-1 MODEL

2012 ◽  
Vol 27 (26) ◽  
pp. 1250156 ◽  
Author(s):  
A. DOFF ◽  
A. A. NATALE
Keyword(s):  
Gauge Symmetry ◽  
Symmetry Breaking ◽  
Dynamical Symmetry ◽  
Mass Scale ◽  
Coupling Constant ◽  
Walking Behavior ◽  
Dynamical Symmetry Breaking ◽  
Dynamical Generation ◽  
Breaking Scale

The gauge symmetry breaking in some versions of 3-3-1 models can be implemented dynamically because at the scale of a few TeVs the U(1)X coupling constant becomes strong. In this work, we consider the dynamical symmetry breaking in a minimal SU(3) TC × SU(3)L × U(1)X model, where we propose a new scheme to cancel the chiral anomalies, including two-index symmetric (6) technifermions, which incorporates naturally the walking behavior in the Technicolor (TC) sector. The composite scalar content of the model is minimal and all the symmetry breaking is implemented by a multiplet of technifermions. The choice of TC representations not only provides the anomaly cancelation with a walking behavior, but is crucial to promote the model's full dynamical symmetry breaking. We consider the dynamical generation of technigluon masses and, depending on the 3-3-1 symmetry breaking scale (μ331), we verify that the technigluon mass is strongly linked to the Z′ mass scale, for instance, if μ331 = 1 TeV , we have MZ′ > 1 TeV only if M TG < 350 GeV .

Invisible axion at an intermediate symmetry breaking scale

1982 ◽  
Vol 109 (5) ◽  
pp. 365-368 ◽  
Author(s):  
David B. Reiss
Keyword(s):  
Symmetry Breaking ◽  
Invisible Axion ◽  
Breaking Scale
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