A measurement of the pion charge radius

Amendolia, S. R.; Badełek, B.; Batignani, G.; Beck, G.A.; Bedeschi, F.; Bellamy, E.H.; Bertolucci, E.; Bettoni, D.; Bilokon, H.; Bologna, G.; Bosisio, L.; Bradaschia, C.; Budinich, Marco; Codino, A.; Counihan, M. J.; Dell’Orso, M.; Piazzoli, B. D’Ettorre; Fabbri, F. L.; Fidecaro, F.; Foà, L.; Focardi, E.; Frank, S.; Giazotto, A.; Giorgi, M. A.; Green, M.G.; Harvey, J.; Heath, G. P.; Landon, M. P. J.; Laurelli, P.; Liello, F.; Mannocchi, G.; March, P.V.; Marrocchesi, P. S.; Menasce, D.; Menzione, A.; Meroni, E.; Milotti, E.; Moroni, L.; Picchi, P.; Ragusa, F.; Ristori, L.; Rolandi, G.; Saltmarsh, C.; Saoucha, A.; Satta, L.; Scribano, A.; Спиллантини, П.; Stefanini, A.; Storey, D.; Strong, J. A.; Тенчини, Р.; Tonelli, G.; Schlippe, W. von; Herwijnen, E. van; Zallo, A.

doi:10.1016/0370-2693(84)90655-5

Cited by 163 publications

(90 citation statements)

References 9 publications

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“…(53); and defined by Eqs. (58) and (60). The shaded oval in the third diagram represents the quark-pion vertex, which we approximate by its pole form.…”

Section: Quark-photon Vertexmentioning

confidence: 99%

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Role of diquark correlations and the pion cloud in nucleon elastic form factors

2014

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Electromagnetic form factors of the nucleon in the space-like region are investigated within the framework of a covariant and confining Nambu-Jona-Lasinio model. The bound state amplitude of the nucleon is obtained as the solution of a relativistic Faddeev equation, where diquark correlations appear naturally as a consequence of the strong coupling in the colour3 qq channel. Pion degrees of freedom are included as a perturbation to the "quark-core" contribution obtained using the Poincaré covariant Faddeev amplitude. While no model parameters are fit to form factor data, excellent agreement is obtained with the empirical nucleon form factors (including the magnetic moments and radii) where pion loop corrections play a critical role for Q 2 1 GeV 2 . Using charge symmetry, the nucleon form factors can be expressed as proton quark sector form factors. The latter are studied in detail, leading, for example, to the conclusion that the d-quark sector of the Dirac form factor is much softer than the u-quark sector, a consequence of the dominance of scalar diquark correlations in the proton wave function. On the other hand, for the proton quark sector Pauli form factors we find that the effect of the pion cloud and axialvector diquark correlations overcomes the effect of scalar diquark dominance, leading to a larger d-quark anomalous magnetic moment and a form factor in the u-quark sector that is slightly softer than in the d-quark sector.

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“…(53); and defined by Eqs. (58) and (60). The shaded oval in the third diagram represents the quark-pion vertex, which we approximate by its pole form.…”

Section: Quark-photon Vertexmentioning

confidence: 99%

“…13, where good agreement with pion form factor data from Refs. [59][60][61][62][63] is seen. At large Q 2 both form factors plateau, where we find…”

Section: Diquark and Meson Form Factorsmentioning

confidence: 99%

Role of diquark correlations and the pion cloud in nucleon elastic form factors

2014

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“…In extension of our previous work [30], we here calculate the ππ phase shift and the pion EM formfactor, |F π | 2 , from our vector correlator and compare them to data [39][40][41][42], in Fig. 10.…”

Section: Vacuum Spectral Functions In the Vector And Axial-vectomentioning

confidence: 99%

Massive Yang–Mills for vector and axial-vector spectral functions at finite temperature

Hohler

Rapp

2016

Annals of Physics

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The hadronic mechanism which leads to chiral symmetry restoration is explored in the context of the ρπa1 system using Massive Yang-Mills, a hadronic effective theory which governs their microscopic interactions. In this approach, vector and axial-vector mesons are implemented as gauge bosons of a local chiral gauge group. We have previously shown that this model can describe the experimentally measured vector and axial-vector spectral functions in vacuum. Here, we carry the analysis to finite temperatures by evaluating medium effects in a pion gas and calculating thermal spectral functions. We find that the spectral peaks in both channels broaden along with a noticeable downward mass shift in the a1 spectral peak and negligible movement of the ρ peak. The approach toward spectral function degeneracy is accompanied by a reduction of chiral order parameters, i.e., the pion decay constant and scalar condensate. Our findings suggest a mechanism where the chiral mass splitting induced in vacuum is burned off. We explore this mechanism and identify future investigations which can further test it.

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“…Let us note that our RQM describes well the experimental data for the pion form factor including the recent points [22]. Let us emphasize that the parameters used in our calculations were obtained from the fitting to the experimental data up to Q 2 0.26 GeV 2 [23]. At that time the data for higher Q 2 was not correlated in different experiments and had significant uncertainties.…”

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confidence: 51%

Electroweak properties ofρ-meson in the instant form of relativistic quantum mechanics

2017

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Abstract. Charge and magnetic radii, magnetic and quadrupole moments of the ρ-meson are calculated in framework of the developed by authors version of the instant form of relativistic quantum mechanics with fixed number of particles (IF RQM). The calculations are performed with different wave functions of quarks in the ρ-meson and using the so-called modified impulse approximation (MIA). The electromagnetic characteristics of ρ-meson are obtained without fitting parameters. The value of the magnetic moment coincides with available experimental data: μ ρ = 2.1 ± 0.5 e/2M ρ .

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A measurement of the pion charge radius

Cited by 163 publications

References 9 publications

Role of diquark correlations and the pion cloud in nucleon elastic form factors

Role of diquark correlations and the pion cloud in nucleon elastic form factors

Massive Yang–Mills for vector and axial-vector spectral functions at finite temperature

Electroweak properties ofρ-meson in the instant form of relativistic quantum mechanics

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