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Relaxing the Electroweak Scale: the Role of Broken dS Symmetry

Recently, a novel mechanism to address the hierarchy problem has been proposed \cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass t...

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Detalles Bibliográficos
Autores principales: Patil, Subodh P., Schwaller, Pedro
Lenguaje:eng
Publicado: 2015
Materias:
Acceso en línea:https://dx.doi.org/10.1007/JHEP02(2016)077
http://cds.cern.ch/record/2039436
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author Patil, Subodh P.
Schwaller, Pedro
author_facet Patil, Subodh P.
Schwaller, Pedro
author_sort Patil, Subodh P.
collection CERN
description Recently, a novel mechanism to address the hierarchy problem has been proposed \cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than $M$ through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale $M$ and the order parameter $\epsilon$ associated with the breaking of dS symmetry, and entertain the possibility that the relaxion could play the role of a curvaton. We find that a successful realization of the mechanism is possible with as few as $\mathcal O (10^3)$ e-foldings, albeit with a reduced cutoff $M \sim 10^6$ GeV for a dark QCD axion and outline a minimal scenario that can be made consistent with CMB observations.
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institution Organización Europea para la Investigación Nuclear
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spelling cern-20394362023-03-14T17:44:29Zdoi:10.1007/JHEP02(2016)077http://cds.cern.ch/record/2039436engPatil, Subodh P.Schwaller, PedroRelaxing the Electroweak Scale: the Role of Broken dS SymmetryParticle Physics - PhenomenologyRecently, a novel mechanism to address the hierarchy problem has been proposed \cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than $M$ through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale $M$ and the order parameter $\epsilon$ associated with the breaking of dS symmetry, and entertain the possibility that the relaxion could play the role of a curvaton. We find that a successful realization of the mechanism is possible with as few as $\mathcal O (10^3)$ e-foldings, albeit with a reduced cutoff $M \sim 10^6$ GeV for a dark QCD axion and outline a minimal scenario that can be made consistent with CMB observations.Recently, a novel mechanism to address the hierarchy problem has been proposed [1], where the hierarchy between weak scale physics and any putative ‘cutoff’ M is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than M through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale M and the order parameter ϵ associated with the breaking of dS symmetry, and entertain the possibility that the relaxion could play the role of a curvaton. We find that a successful realization of the mechanism is possible with as few as $ \mathcal{O}\left(1{0}^3\right) $ e-foldings, albeit with a reduced cutoff M ∼ 10$^{6}$ GeV for a dark QCD axion and outline a minimal scenario that can be made consistent with CMB observations.Recently, a novel mechanism to address the hierarchy problem has been proposed \cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than $M$ through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale $M$ and the order parameter $\epsilon$ associated with the breaking of dS symmetry, and entertain the possibility that the relaxion could play the role of a curvaton. We find that a successful realization of the mechanism is possible with as few as $\mathcal O (10^3)$ e-foldings, albeit with a reduced cutoff $M \sim 10^6$ GeV for a dark QCD axion and outline a minimal scenario that can be made consistent with CMB observations.arXiv:1507.08649CERN-PH-TH-2015-179CERN-PH-TH-2015-179oai:cds.cern.ch:20394362015-07-30
spellingShingle Particle Physics - Phenomenology
Patil, Subodh P.
Schwaller, Pedro
Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title_full Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title_fullStr Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title_full_unstemmed Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title_short Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
title_sort relaxing the electroweak scale: the role of broken ds symmetry
topic Particle Physics - Phenomenology
url https://dx.doi.org/10.1007/JHEP02(2016)077
http://cds.cern.ch/record/2039436
work_keys_str_mv AT patilsubodhp relaxingtheelectroweakscaletheroleofbrokendssymmetry
AT schwallerpedro relaxingtheelectroweakscaletheroleofbrokendssymmetry