Updated study of the 
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 mixing and the thermal properties of light pseudoscalar mesons at low temperatures

Gu, Xiaodong; Duan, Chun-Gui; Guo, Zhi-Hui

doi:10.1103/physrevd.98.034007

Cited by 21 publications

(31 citation statements)

References 60 publications

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“…REV. D 99, 014007 (2019) 014007-9 recent analysis within the framework of the Uð3Þ chiral perturbation theory found that the (small) increase of the masses of π, K, and η after around T ∼ 120 MeV, is accompanied by the decrease of the η 0 mass, but only by some 15 MeV [55]. Admittedly, the crossover transition leaves more space for model dependence, since some model changes that would make the crossover even smoother would reduce our η 0 mass decrease.…”

Section: Summary Discussion and Conclusionmentioning

confidence: 99%

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
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The approach to the η 0-η complex employing chirally well-behaved quark-antiquark bound states and incorporating the non-Abelian axial anomaly of QCD through the generalization of the Witten-Veneziano relation is extended to finite temperatures. Employing the chiral condensate has led to a sharp chiral and U A ð1Þ symmetry restoration, but with the condensates of quarks with realistic explicit chiral symmetry breaking-which exhibit a smooth, crossover chiral symmetry restoration in qualitative agreement with lattice QCD results-we get a crossover U A ð1Þ transition with a smooth and gradual melting of anomalous mass contributions. In this way, we obtain a substantial decrease in the η 0 mass around the chiral transition temperature, but no decrease in the η mass. This is consistent with current empirical evidence.

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Section: Summary Discussion and Conclusionmentioning

confidence: 99%

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
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“…Of course, dynamical models of QCD can access only much smaller range of temperatures than lattice, where T ∼ 20 T c has already been reached [71]. (On the other hand, the thermal behavior of the U A (1) anomaly could not be accessed in chiral perturbation theory [89]. )…”

Section: Summary and Discussionmentioning

confidence: 99%

Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the UA(1) Symmetry

2019

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The temperature (T) dependence of the axion mass is predicted for T ′ s up to ∼ 2.3× the chiral restoration temperature of QCD. The axion is related to the U A (1) anomaly. The squared axion mass m a (T) 2 is, modulo the presently undetermined scale of spontaneous breaking of Peccei-Quinn symmetry f a (squared), equal to QCD topological susceptibility χ(T) for all T. We obtain χ(T) by using quark condensates calculated in two effective Dyson-Schwinger models of nonperturbative QCD. They exhibit the correct chiral behavior, including the dynamical breaking of chiral symmetry and its restoration at high T. This is reflected in the U A (1) symmetry breaking and restoration through χ(T). In our previous studies, such χ(T) yields the T-dependence of the U A (1)-anomaly-influenced masses of η ′ and η mesons consistent with experiment. This in turn supports our prediction for the T-dependence of the axion mass. Another support is a rather good agreement with the pertinent lattice results. This agreement is not spoiled by our varying u and d quark mass parameters out of the isospin limit.2 of 23 mass-eigenstate basis, one diagonalizes the mass matrix, and the corresponding chiral transformation changes θ by arg det M. Hence, in the Standard Model the coefficient of the Q ∝ FF term is in fact. Therefore, to be precise, we change our notation toθ-term, L θ → Lθ.Since CP is not a symmetry of the Standard Model, there is no a priori reasonθ, which results from the contributions from both the strong and weak interactions, should vanish. And yet, the experimental bound on it is extremely low, θ < 10 −10 [9], and in fact consistent with zero. Therefore, the mystery of the vanishing strong CP violation is: why isθ so small?The most satisfactory answer till this very day has been provided by axions, even though the original variant has been ruled out [1]. In the meantime, they turned out to be very important also for cosmology, as promising candidates for dark matter-see from relatively recent references such as [10,11] to the earliest papers [12][13][14]. (For an example of a broader review of axion physics, see [15].) It is thus no wonder that ever since the original proposal of the axion mechanism [2-5] in 1977-1978, many theorists kept developing various ideas on this theoretically much needed object, trying to pinpoint the properties of this elusive particle and increase chances of finding it.However, to no avail. There have even been some speculations that the axion is hidden in plain sight, by being experimentally found, paradoxically, already years before it was conjectured theoretically: namely, that the axion should in fact be identified with the well-known η ′ meson with a minuscule admixture of a pseudoscalar composite of neutrinos [16]. Nevertheless, while an intimate relation between the axion and η ′ doubtlessly exists, reformulations of the axion theory, let alone so drastic ones, are in fact not needed to exploit this axion-η ′ relationship: thanks to the fact that both of their masses stem from the axial anomaly...

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“…For the LO mass M 0 of the η 0 , we will take the value M 0 = 820 MeV that has been recently determined in Ref. [26] by fitting the updated lattice data of the η-η ′ mixing.…”

Section: Introductionmentioning

confidence: 99%

Thermal behaviors of light scalar resonances at low temperatures

2019

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We study the thermal properties of the lowest multiplet of the QCD light-flavor scalar resonances, including the f 0 (500)/σ, K * 0 (700)/κ, f 0 (980) and a 0 (980), in the framework of unitarized U (3) chiral perturbation theory. After the successful fits to the meson-meson scattering inputs, such as the phase shifts and inelasticities, we obtain the unknown parameters and further calculate the resonance poles and their residues at zero temperature. By including the finite-temperature effects in the unitarized meson-meson scattering amplitudes, the thermal behaviors of the scalar resonance poles in the complex energy plane are studied. The masses of σ and κ are found to considerably decrease when increasing the temperatures, while their widths turn out to be still large when the temperatures reach around 200 MeV. In contrast, both the masses and widths of the f 0 (980) and a 0 (980) are only slightly changed.

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Updated study of the η−η′ mixing and the thermal properties of light pseudoscalar mesons at low temperatures

Cited by 21 publications

References 60 publications

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
View full text Add to dashboard Cite

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
View full text Add to dashboard Cite

Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the UA(1) Symmetry

Thermal behaviors of light scalar resonances at low temperatures

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Updated study of the η−η′ mixing and the thermal properties of light pseudoscalar mesons at low temperatures

Cited by 21 publications

References 60 publications

η′ and η mesons at high T when the Horvatić1, Kekez2, Klabučar3 2019Phys. Rev. D249800View full textAdd to dashboardCite

η′ and η mesons at high T when the Horvatić1, Kekez2, Klabučar3 2019Phys. Rev. D249800View full textAdd to dashboardCite

Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the UA(1) Symmetry

Thermal behaviors of light scalar resonances at low temperatures

Contact Info

Product

Resources

About

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
View full text Add to dashboard Cite

η′ and η mesons at high T when the
Horvatić
¹
,
Kekez
²
,
Klabučar
³

2019
Phys. Rev. D
24
9
80
0
View full text Add to dashboard Cite