An M theory solution to the strong CP-problem, and constraints on the axiverse

Acharya, B. S.; Bobkov, Konstantin; Kumar, Piyush

doi:10.1007/jhep11(2010)105

Cited by 186 publications

(169 citation statements)

References 68 publications

(207 reference statements)

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“…For example, one gets an axion for each closed submanifold in the extra dimensions. This can be a very large number, possibly more than a 100, a fact that has triggered the discussion about a string axiverse [43][44][45]. In these constructions one finds, next to the axion, additional axionlike particles with masses distributed uniformly in the logarithm.…”

Section: Alps From String Theorymentioning

confidence: 99%

3.55 keV hint for decaying axionlike particle dark matter

Jaeckel¹,

2014

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Recently, indications for an emission line at 3.55 keV have been found in the combined spectra of a large number of galaxy clusters and also in Andromeda. This line could not be identified with any known spectral line. It is tempting to speculate that it has its origin in the decay of a particle contributing all or part of the dark matter. In this paper we want to point out that axionlike particles being all or part of the dark matter are an ideal candidate to produce such a feature. More importantly the parameter values necessary are quite feasible in extensions of the Standard Model based on string theory and could be linked up to a variety of other intriguing phenomena, which also potentially allow for new tests of this speculation.

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Section: Alps From String Theorymentioning

confidence: 99%

3.55 keV hint for decaying axionlike particle dark matter

Jaeckel¹,

2014

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“…The number density of H 2 and H I are given by n H 2 (z, r) = 4.06 cm −3 exp − r 2.57kpc − |z| 0.08kpc (6) where r here is the cylindrical radial coordinate n H I (z, r) = 0.32 cm −3 exp − r 18.24kpc − |z| 0.52kpc if ρ ≥ 2.75kpc; 0 if ρ < 2.75 kpc.…”

Section: Distribution Of Hydrogen and Free Electronsmentioning

confidence: 99%

“…Axion like fields are often found in string theory compactifications [4,5,6], generically with an inverse coupling (corresponding to the Peccei Quinn Scale) of around M ∼ 10 16 GeV, however, lower values of M can be obtained depending upon the details of the compactification [4,7].…”

Section: Introductionmentioning

confidence: 99%

Axionic dark radiation and the Milky Way’s magnetic field

Fairbairn

2014

Phys. Rev. D

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Recently it has been suggested that dark radiation in the form of axions produced during the decay of string theory moduli fields could be responsible for the soft x-ray excess in galaxy clusters. These soft X-ray photons come about due to the conversion of these axions into photons in the magnetic fields of the clusters. In this work we calculate the conversion of axionic dark radiation into X-ray photons in the magnetic field of our own Galaxy. We consider ∆N ν ∼ 0.5 worth of dark radiation made up of axions with energy of order 0.1-1 keV. We show that it is possible, if a little optimistic, to explain the large regions of X-ray emission located above and below the centre of the Galactic plane detected in the 3/4 keV ROSAT all sky map completely due to the conversion of dark radiation into photons with an inverse axion-photon coupling of M ∼ 3 × 10 13 GeV and an axion mass of m ≤ 10 −12 eV. Different parameter values could explain both these features and the 3/4 keV X-ray background. More conservatively, these X-ray observations are a good way to constrain such models of axionic dark radiation.

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“…The energy density in these oscillations can be dark matter [15,16]. Other types of light bosons, often called axionlike particles (ALPs), have attracted significant attention [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. These receive a potential (and a mass) from non-QCD sources and are less constrained than the QCD axion.…”

Section: Introductionmentioning

confidence: 99%

Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr)

et al. 2014

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We propose an experiment to search for QCD axion and axionlike-particle dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of an electric field. Precision magnetometry can be used to search for such precession. An initial phase of this experiment could cover many orders of magnitude in axionlike-particle parameter space beyond the current astrophysical and laboratory limits. And with established techniques, the proposed experimental scheme has sensitivity to QCD axion masses m a ≲ 10 −9 eV, corresponding to theoretically well-motivated axion decay constants f a ≳ 10 16 GeV. With further improvements, this experiment could ultimately cover the entire range of masses m a ≲ μ eV, complementary to cavity searches.

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An M theory solution to the strong CP-problem, and constraints on the axiverse

Cited by 186 publications

References 68 publications

3.55 keV hint for decaying axionlike particle dark matter

3.55 keV hint for decaying axionlike particle dark matter

Axionic dark radiation and the Milky Way’s magnetic field

Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr)

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