Chiral symmetry breaking and meson-nucleon sigma commutators: A review

Reya, E.

doi:10.1103/revmodphys.46.545

Cited by 150 publications

(83 citation statements)

References 135 publications

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“…The customary procedure is to go through the following steps (see, for instance, Ref. [17]): i) By use of phase-shift analysis and dispersion relations, from the experimental data of low-energy pion-nucleon scattering, one derives the quantity…”

Section: Neutralino-nucleus Elastic Cross-sectionmentioning

confidence: 99%

Implications for relic neutralinos of the theoretical uncertainties in the neutralino–nucleon cross section

Bottino

Donato

Fornengo

et al. 2000

Astroparticle Physics

172

179

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We discuss the effect induced on the neutralino-nucleon cross-section by the present uncertainties in the values of the quark masses and of the quark scalar densities in the nucleon. We examine the implications of this aspect on the determination of the neutralino cosmological properties, as derived from measurements of WIMP direct detection. We show that, within current theoretical uncertainties, the DAMA annual modulation data are compatible with a neutralino as a major dark matter component, to an extent which is even larger than the one previously derived. We also comment on implications of the mentioned uncertainties for experiments of indirect dark matter detection. *

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Section: Neutralino-nucleus Elastic Cross-sectionmentioning

confidence: 99%

Implications for relic neutralinos of the theoretical uncertainties in the neutralino–nucleon cross section

Bottino

Donato

Fornengo

et al. 2000

Astroparticle Physics

172

179

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“…By comparing the scalar density and the vector charge, it is possible to probe how relativistic the particles are. The isoscalar quark scalar density is known * yamanaka@ruby.scphys.kyoto-u.ac.jp as the pion-nucleon sigma term σ πN ≡ m q N |qq|N , and many phenomenological [1][2][3][4] and lattice QCD [5][6][7][8][9] analyses have been done. It is also a useful input in the direct search for dark matter [10], since it gives the strength of the interaction of the nucleon with the new particles beyond the standard model, such as the neutralino in supersymmetric models [11].…”

Section: Introductionmentioning

confidence: 99%

Quark scalar, axial, and pseudoscalar charges in the Schwinger-Dyson formalism

et al. 2014

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We calculate the scalar, axial, and pseudoscalar charges of the quark in the Schwinger-Dyson formalism of Landau gauge QCD. It is found that the dressed quark scalar density of the valence quark is significantly enhanced against the bare quark contribution, and the result explains qualitatively the phenomenologically known value of the pion-nucleon sigma term and also that given by lattice QCD. Moreover, we show that the Richardson's interquark potential suppresses the quark scalar density in the Higashjima-Miransky approximation. This fact suggests that the quark scalar density is an observable that is sensitive to quark confinement. For the quark axial charge, we find that it is suppressed due to the gluon dynamics. The result of the quenched analysis agrees qualitatively with the experimental data of the isovector axial coupling constant gA. We show that the suppression of the quenched axial charge is due to a mechanism similar to that of the quark tensor charge. In the Schwinger-Dyson equation with the leading unquenching quark-loop contribution the quark axial charge is more suppressed, due to the anomaly effect. The quark pseudoscalar density is found to be large, and is divergent as the bare quark becomes massless. This result is in agreement with the phenomenological current algebraic analysis, and explains well the dominance of the pion-pole contribution.

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“…Extracting the strangeness sigma term is significantly more challenging, because the same prescription would lead to both a poorly converged low-energy relation and a large extrapolation of K À N scattering to the ChengDashen point-see Reya [26]. A much more practical…”

mentioning

confidence: 99%