The topological susceptibility in finite temperature QCD and axion cosmology

Petreczky, Péter; Schadler, Hans-Peter; Sharma, Sayantan

doi:10.1016/j.physletb.2016.09.063

Cited by 198 publications

(306 citation statements)

References 66 publications

(102 reference statements)

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“…T (a) osc < Λ. Recent lattice calculations [35][36][37][38] show that the axion mass index is well described by the dilute instanton gas approximation, γ 8, in high temperature regimes. The red region is excluded by BBN because of the late decays of the saxion.…”

Section: Misalignment Axion Contribution To Dark Mattermentioning

confidence: 99%

Saxion cosmology for thermalized gravitino dark matter

DʼEramo

Hall

et al. 2017

J. High Energ. Phys.

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In all supersymmetric theories, gravitinos, with mass suppressed by the Planck scale, are an obvious candidate for dark matter; but if gravitinos ever reached thermal equilibrium, such dark matter is apparently either too abundant or too hot, and is excluded. However, in theories with an axion, a saxion condensate is generated during an early era of cosmological history and its late decay dilutes dark matter. We show that such dilution allows previously thermalized gravitinos to account for the observed dark matter over very wide ranges of gravitino mass, keV < m 3/2 < TeV, axion decay constant, 10 9 GeV < f a < 10 16 GeV, and saxion mass, 10 MeV < m s < 100 TeV. Constraints on this parameter space are studied from BBN, supersymmetry breaking, gravitino and axino production from freeze-in and saxion decay, and from axion production from both misalignment and parametric resonance mechanisms. Large allowed regions of (m 3/2 , f a , m s ) remain, but differ for DFSZ and KSVZ theories. Superpartner production at colliders may lead to events with displaced vertices and kinks, and may contain saxions decaying to (W W, ZZ, hh), gg, γγ or a pair of Standard Model fermions. Freeze-in may lead to a sub-dominant warm component of gravitino dark matter, and saxion decay to axions may lead to dark radiation.

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Section: Misalignment Axion Contribution To Dark Mattermentioning

confidence: 99%

Saxion cosmology for thermalized gravitino dark matter

DʼEramo

Hall

et al. 2017

J. High Energ. Phys.

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“…Although χ top is particularly difficult to measure in the lattice [5,29,30], its vanishing or asymptotic reduction indicates Uð1Þ A restoration, as the system becomes less sensitive to the P-breaking anomaly contribution parametrized in the θ term [39].…”

Section: Consequences For Chiral Symmetry Restorationmentioning

confidence: 99%

Patterns and partners for chiral symmetry restoration

Nicola

Elvira

2018

Phys. Rev. D

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We present and analyze a new set of Ward Identities which shed light on the distinction between different patterns of chiral symmetry restoration in QCD, namely Oð4Þ vs Oð4Þ × Uð1Þ A . The degeneracy of chiral partners for all scalar and pseudoscalar meson nonet members is studied through their corresponding correlators. Around chiral symmetry degeneration of Oð4Þ partners, our analysis predicts that Uð1Þ A partners are also degenerated. Our analysis also leads to I ¼ 1=2 scalar-pseudoscalar partner degeneration at exact chiral restoration and supports ideal mixing between the η-η 0 and the f 0 ð500Þ-f 0 ð980Þ mesons at Oð4Þ × Uð1Þ A restoration, with a possible range where the pseudoscalar mixing vanishes if the two transitions are well separated. We test our results with lattice data and provide further relevant observables regarding chiral and Uð1Þ A restoration for future lattice and model analyses.

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“…The last factor in (19) comes from the normalization of the Dirac operator. g i vanishes when the Ginsparg-Wilson relation is exactly satisfied.…”

Section: (M)mentioning

confidence: 99%

Evidence of effective axialU(1)symmetry restoration at high temperature QCD

et al. 2017

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We study the axial U (1) symmetry at finite temperature in two-flavor lattice QCD. Employing the Möbius domain-wall fermions, we generate gauge configurations slightly above the critical temperature T c with different lattice sizes L = 2-4 fm. Our action allows frequent topology tunneling while keeping good chiral symmetry close enough to that of overlap fermions. This allows us to recover full chiral symmetry by an overlap/domain-wall reweighting. Above the phase transition, a strong suppression of the low-lying modes is observed in both of overlap and domainwall Dirac spectra. We, however, find a sizable violation of the Ginsparg-Wilson relation in the Möbius domain-wall Dirac eigenmodes, which dominates the signals of the axial U (1) symmetry breaking near the chiral limit. We also find that the use of overlap fermion only in the valence sector is dangerous since it suffers from the artifacts due to partial quenching. Reweighting the Möbius domain-wall fermion determinant to that of the overlap fermion, we observe the axial U (1) breaking to vanish in the chiral limit, which is stable against the changes of the lattice volume and lattice spacing.2

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The topological susceptibility in finite temperature QCD and axion cosmology

Cited by 198 publications

References 66 publications

Saxion cosmology for thermalized gravitino dark matter

Saxion cosmology for thermalized gravitino dark matter

Patterns and partners for chiral symmetry restoration

Evidence of effective axialU(1)symmetry restoration at high temperature QCD

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