Asymptotic estimates of the pion charge form factor

Krutov, A. F.; Troitsky, V. E.

doi:10.1007/bf02557133

Cited by 28 publications

(44 citation statements)

References 16 publications

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“…It is shown that the form-factor dependence on the choice of the model for quark wave function in pion is weak, while the dependence on the constituent-quark mass is rather significant. It is possible to estimate the mass of constituent quark and the sum of anomalous magnetic moments of u-andd-quarks from the JLab experiments.PACS numbers: 12.39, 12.60.R, 13.40.G At present time the constituent quark model (CQM) is widely and successfully used for the description of hadron properties at low and intermediate energies [1][2][3][4][5][6][7][8][9][10][11][12][13]. The reasons for this are well known: first, CQM uses the physically adequate degrees of freedom; second, CQM describes nonperturbative effects.…”

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confidence: 99%

On a possible estimation of the constituent-quark parameters from Jefferson Lab experiments on the pion form factor

2001

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The charge form factor of the pion is calculated for momentum transfer range of Jefferson Lab experiments. The approach is based on the instant form of the relativistic Hamiltonian dynamics. It is shown that the form-factor dependence on the choice of the model for quark wave function in pion is weak, while the dependence on the constituent-quark mass is rather significant. It is possible to estimate the mass of constituent quark and the sum of anomalous magnetic moments of u-andd-quarks from the JLab experiments.PACS numbers: 12.39, 12.60.R, 13.40.G At present time the constituent quark model (CQM) is widely and successfully used for the description of hadron properties at low and intermediate energies [1][2][3][4][5][6][7][8][9][10][11][12][13]. The reasons for this are well known: first, CQM uses the physically adequate degrees of freedom; second, CQM describes nonperturbative effects. These facts give a possibility to use CQM for the investigation of the so called "soft" structure of hadrons, e.g. in exclusive processes, in contrast to QCD (see, e.g. [14]).The main feature of CQM versus QCD is the extraction of finite number of the most important degrees of freedom needed to describe the hadron. All dynamical effects of QCD are incorporated in CQM through the effective (constituent) quark mass and internal quark structure in terms of quark form factors. So, in the framework of CQM constituent quarks have all the material properties of free particles and interact with each other through the confinement potential. This means that constituent quark is characterized by an effective mass, a mean-square-radius (MSR) and an anomalous magnetic moment. Let us remark that the concept of extended constituent quarks also appears in some quantum field theory models, for example, in Nambu-Jona-Lasinio model with spontaneous chiral symmetry breaking [15]. In this context one can imagine that CQM is initiated by QCD. However, it is very important to remind ourselves that CQM is not a direct consequence of QCD, but a very * Electronic address: krutov@info.ssu.samara.ru † Electronic address: troitsky@theory.npi.msu.su successful phenomenological model [16]. For the description of electroweak properties it is necessary to take into account the relativistic effects, especially large in systems of light quarks. We will use the relativistic Hamiltonian dynamics (RHD) [17], which is one of approaches to describe relativistic properties of CQM.In the present paper we discuss the dependence of electromagnetic pion form factor on the internal quark structure. The interest to this problem is due particularly to a possible interpretation of current experiments in Jefferson Lab on the measurement of pion form factor [18] in the range of momentum transfer 0.5(GeV /c) 2 < Q 2 < 5(GeV /c) 2 . Using one of relativistic forms of CQM we obtain that pion form factor in this region of Q 2 depends strongly on the constituent quark mass, while the dependence on model quark interaction in pion is weak. This fact gives hope that it could be possi...

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On a possible estimation of the constituent-quark parameters from Jefferson Lab experiments on the pion form factor

2001

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“…(18), (19) b π,ρ are parameters of wave functions for pion and ρ-meson, respectively. The electromagnetic form factors of constituent quarks in (16) are taken in the form [1,17]:…”

Section: Quarks-2016mentioning

confidence: 99%

“…So, it is obtained in Ref. [17] that The asymptotics of the pion electromagnetic form factor F π at momenta transfer Q 2 → ∞ has been determined [20][21][22], in the QCD frameworks, as…”

Section: Asymptotics Of the Pion Form Factor At High Momentum Transfersmentioning

confidence: 99%

Poincaré-invariant constituent quark model for light mesons: capabilities and constraints

2016

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Abstract. We present a brief survey of some results on electroweak properties of composite systems that are obtained in the frameworks of our version of the instant form of relativistic quantum mechanics (RQM). Our approach describes well the π-and the ρ-mesons in wide range of momentum transfers Q 2 . At large Q 2 the obtained pion form factor asymptotics coincides with that of QCD predictions. The method permits to perform analytic continuation of pion form factor to complex plane of momentum transfers that is in accordance with predictions of quantum field theory.

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“…These re- lationships can also be exploited to construct equivalent current operators for models with different forms of dynamics. Existing calculations show that the representation of the currents in different forms of dynamics can be very different [8,9,11,[13][14][15][16]. This same freedom also exists in local quantum field theory, where theories in the same Borchers class [17] are scattering equivalent.…”

Section: ͑14͒mentioning

confidence: 99%

Pointlike constituent quarks and scattering equivalences

Sengbusch

Polyzou

2004

Phys. Rev. C

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In this paper scattering equivalences are used to simplify current operators in constituent quark models. The simplicity of the method is illustrated by applying it to a relativistic constituent quark model that fits the meson mass spectrum. This model requires a non-trivial constituent quark current operator to fit the pion form factor data. A model with a different confining interaction, that has the identical spectrum and can reproduce the measured pion form factor using only point-like constituent quark impulse currents is constructed. Both the original and transformed models are relativistic direct-interaction models with a light-front kinematic subgroup.Comment: 12 pages, 6 figures, corrected caption on fig

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Asymptotic estimates of the pion charge form factor

Cited by 28 publications

References 16 publications

On a possible estimation of the constituent-quark parameters from Jefferson Lab experiments on the pion form factor

On a possible estimation of the constituent-quark parameters from Jefferson Lab experiments on the pion form factor

Poincaré-invariant constituent quark model for light mesons: capabilities and constraints

Pointlike constituent quarks and scattering equivalences

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