Photon production of axionic cold dark matter

Lee, Da-Shin; Ng, Kin-Wang

doi:10.1103/physrevd.61.085003

Cited by 36 publications

(52 citation statements)

References 30 publications

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“…Moreover the mass obtained from Lattice calculations for the 0 ++ glueball candidate is around 1600 − 1700 MeV with the uncertainty of 100 MeV. It is noteworthy that in lattice calculations the mixing of glueball field with isosinglet scalar mesons was not considered [62,[64][65][66] .…”

Section: Introductionmentioning

confidence: 99%

“…At present there is no agreement in literature that among the two strongest candidates, i.e., f 0 (1500) and f 0 (1710), which one is the lightest scalar glueball. While in [23,[57][58][59][60][61], f 0 (1500) is believed to be mostly gluonic, in [62,63] f 0 (1710) was argued to be an unmixed scalar glueball. Moreover the mass obtained from Lattice calculations for the 0 ++ glueball candidate is around 1600 − 1700 MeV with the uncertainty of 100 MeV.…”

Section: Introductionmentioning

confidence: 99%

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Mixing among lowest-lying scalar mesons and scalar glueball

2018

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Scalar glueball is implemented in single nonet linear sigma model (SNLSM) which basically includes lowest lying scalar and pseudoscalar mesons. Our new version of SNLSM involves mixing among scalar matter fields and glueball field which is enforced by scale symmetry considerations and the associated anomaly. Performing iterative Monte Carlo simulations, it is found that among the three candidates of scalar glueball, i.e., f0(1370), f0(1500) and f0 (1710), only f0 (1500) is predominately a glueball state with the mass prediction of 1.566 ± 0.046 GeV and the other two are predominately quarkonium. The ππ, πK and πη scatterings are reinvestigated in the presence of scalar glueball and it is found that the overall behavior of the real part of the K-matrix unitarized ππ scattering amplitude is more compatible with observed data compared with the case of SNLSM without glueball. We have also presented the predictions of the model for the masses and decay widths of the scalars obtained from the poles of the K-matrix unitarized ππ, πK and πη scattering amplitudes. Moreover the ππ scattering phase shift predicted by our model is compared with the prediction of generalized linear sigma model (GLSM) which contains two nonets of scalar mesons and two nonets of pseudoscalar mesons (a quark-antiquark nonet and a four-quark nonet). Despite the fact that at this stage our model lacks the second meson nonet above 1 GeV, its prediction for the ππ scattering phase shift is close to the prediction of GLSM for √ s < 1.1 GeV and in better agreement with experimental data for √ s > 1.1 GeV in comparison with GLSM.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mixing among lowest-lying scalar mesons and scalar glueball

2018

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“…The scalar isoscalar sector of the QCD spectrum up to 2 GeV has been of high theoretical and experimental interest for many years. One of the main motivations for these investigations is the hunt for glueballs: their lightest representatives are predicted to occur in the mass range between 1600 and 1700 MeV with quantum numbers 0 ++ [1][2][3][4]. The most straightforward way to identify glueball candidates is to count states with and without flavor quantum number and see if there are supernumerary isoscalar states; see, e.g., the minireview on non-qq states provided by the Particle Data Group (PDG) [5] or the reviews Refs.…”

Section: Introductionmentioning

confidence: 99%

A new parametrization for the scalar pion form factors

Ropertz¹,

Hanhart

Kubis³

2018

Eur. Phys. J. C

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We derive a new parametrization for the scalar pion form factors that allows us to analyze data over a large energy range via the inclusion of resonances, and at the same time to ensure consistency with the high-accuracy dispersive representations available at low energies. As an application the formalism is used to extract resonance properties of excited scalar mesons from data forB 0 s → J/ψππ. In particular we find for the pole positions of f 0 (1500) and f 0 (2020) 1465±18−i(50±9) MeV and 1910±50−i(199±40) MeV, respectively. In addition, from their residues we calculate the respective branching ratios into ππ to be (58 ± 31)% and (1.3 ± 1.8)%.

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“…The slightness of the effects of a non-helical magnetic field on the cosmic evolution of the axion field discussed in literature (see, e.g., [17]) can easily be understood: even though the axion itself produces helicity in the presence of an external magnetic field [2,6,18] and therefore its evolution is modified, the effect is negligible since the helicity produced by the axion itself is small. However, if another mechanism were responsible for the production of a significant amount of helicity, the consequences on the axion relic abundance today could be enormous.…”

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confidence: 99%

Production of Axions by Cosmic Magnetic Helicity

Campanelli

Giannotti

2006

Phys. Rev. Lett.

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We investigate the effects of an external magnetic helicity production on the evolution of the cosmic axion field. It is shown that a helicity larger than (f ew × 10 −15 G) 2 Mpc, if produced at temperatures above a few GeV, is in contradiction with the existence of the axion, since it would produce too much of an axion relic abundance.PACS numbers: 14.80. Mz, 98.62.En Recently, the topic of cosmic magnetic helicity generation and phenomenology has been widely discussed (see, e.g., [1,2,3,4,5,6,7,8]). An in depth study of this very peculiar quantity could help in understanding the nature of the cosmic magnetic field itself and its generation. Magnetic helicity is defined aswhereis the electromagnetic field. In a flat universe described by a Robertson-Walker metric, ds 2 = dt 2 −R 2 dx 2 , where R(t) is the expansion parameter normalized so that at the present time t 0 , R(t 0 ) = 1, the electric and magnetic fields are defined as E = −R −1Ȧand B = R −2 ∇ × A, where a dot indicates the derivative with respect to the cosmic time t. Hence, the helicity can be written asIt should be noted that in the literature the definition of H B is usually given without the factor R 2 . In any case, the two definitions coincide at the present time. However we note that, since the early universe is a very good conductor, magnetic fields are frozen into the plasma and then B scales in time as B ∝ R −2 [3]. Therefore, magnetic helicity, as defined in Eq. (1), remains constant (after its generation).The magnetic helicity is related to the topological properties of the magnetic field, it is a CP −odd pseudoscalar quantity and, if different from zero, would reveal a macroscopic P and CP violation in the universe. Let us introduce the magnetic energy and magnetic helicity spectra, respectively, where B(k) and A(k) are the magnetic field and the vector potential in Fourier space and k = |k|.In terms of the spectra, the magnetic energy, E B (t) = (1/2V ) V d 3 x B 2 (x, t), and the magnetic helicity are E B = dk E B , and H B = dk H B . From the above definitions it follows that any magnetic field configuration satisfies the inequality. A straightforward integration in k leads to the so-called "realizability" condition, |H B | ≤ H max B = 2R 3 ξ B E B , which fixes the maximal helicity associated with a given magnetic field configuration. Here, ξ B (t) = 2πR dk k −1 E B (k, t)/E B is the magnetic field correlation length. Therefore, bounds on the magnetic field can be directly translated into bounds on magnetic helicity. Before discussing this point more deeply, it is useful to introduce the following parametrization for the helicity produced at the temperature T * : (2) where g * and g * S count the total numbers of effectively massless degrees of freedom referring to the energy and entropy density of the universe, respectively. (From now on, g * and g * S will be considered equal.) The choice r = 1 gives the maximal helicity associated with a magnetic field correlated on the Hubble scale, ξ B = H −1 (H is the Hubble parameter), and ...

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Photon production of axionic cold dark matter

Cited by 36 publications

References 30 publications

Mixing among lowest-lying scalar mesons and scalar glueball

Mixing among lowest-lying scalar mesons and scalar glueball

A new parametrization for the scalar pion form factors

Production of Axions by Cosmic Magnetic Helicity

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