Properties of the πη, $ \eta{^\prime}$ ,σ, f0(980) and a0(980) mesons and their relevance for the polarizabilities of the nucleon

J. Phys. G: Nucl. Part. Phys.

2011

The scalar mesons σ(600), κ(800), f 0 (980) and a 0 (980) together with the pseudo Goldstone bosons π, K and η may be considered as the Higgs sector of strong interaction. After a long time of uncertainty about the internal structure of the scalar mesons there now seems to be consistency which is in line with the major parts of experimental observations. Great progress has been made by introducing the unified model of Close and Törnqvist. This model states that scalar mesons below 1 GeV may be understood as q 2q2 in S-wave with some qq in P -wave in the center, further out they rearrange as (qq)2 and finally as meson-meson states. The P -wave component inherent in the structure of the neutral scalar mesons can be understood as a doorway state for the formation of the scalar meson via two-photon fusion, whereas in nucleon Compton scattering these P-wave components serve as intermediate states. The masses of the scalar mesons are predicted in terms of spontaneous and explicit symmetry breaking.

“…In case of scalar mesons the same result is obtained except for the effects of the kinematical factor (see [3] and references therein)…”

Section: Two-photon Widths and Doorway-structure Of Scalar Mesonssupporting

confidence: 67%

Section: The Qq (Qq)supporting

confidence: 62%

Section: The Qq (Qq)supporting

confidence: 62%

Section: Two-photon Widths and Doorway-structure Of Scalar Mesonsmentioning

confidence: 99%

See 2 more Smart Citations

Structure of scalar mesons and the Higgs sector of strong interaction

J. Phys. G: Nucl. Part. Phys.

2011

“…These recent investigations have shown [9,10,[19][20][21][22] that a systematic study of all partial resonant and nonresonant photoexcitation processes of the nucleon and of their relevance for the fundamental structure constants of the nucleon as there are the electric polarizability (α), the magnetic polarizability (β) and the backward spin-polarizability (γ π ) is essential for an understanding of the electromagnetic structure of the nucleon. In addition it has been found that the structure of the constituent quarks and their coupling to pseudoscalar and scalar mesons is important for the understanding of the electric and magnetic polarizabilities and of the backward spin-polarizability.…”

Section: Introductionmentioning

confidence: 99%

Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon

2010

Eur. Phys. J. C

It is shown that the Quark-Level Linear σ Model (QLLσ M) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with experimental data. The bare mass of the σ meson is predicted to be m σ = 666 MeV and the twophoton width Γ (σ → γ γ ) = (2.6 ± 0.3) keV. It is argued that the mass predicted by the QLLσ M corresponds to the γ γ → σ → NN reaction, i.e. to a t-channel pole of the γ N → Nγ reaction. Large-angle Compton scattering experiments revealing effects of the σ meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of the strong interaction while being a part of the constituent quark.

Nambu's Nobel Prize, the meson and the mass of visible matter

2014

Annalen der Physik

The electroweak Higgs boson has been discovered in ongoing experiments at the LHC, leading to a mass of this particle of 126 GeV. This Higgs boson mediates the generation of mass for elementary particles, including the mass of elementary (current) quarks. These current-quark masses leave 98% of the mass of the atom unexplained. This large fraction is mediated by strong interaction, where instead of the Higgs boson the σ meson is the mediating particle. Though already introduced in 1957 by Schwinger, the σ meson has been integrated out in many theories of hadron properties because it had not been observed and was doubted to exist. With the observation of the σ meson in recent experiments on Compton scattering by the nucleon at MAMI (Mainz) it has become timely to review the status of experimental and theoretical researches on this topic.