Improved effective action for light quarks beyond the chiral limit

Musakhanov, M.M.

doi:10.1007/s100529900017

Cited by 39 publications

(54 citation statements)

References 13 publications

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“…where the designates the Lagrangian multiplier to make the action exponent [16]. Moreover, we have introduced an arbitrary massive parameter M to make the argument of the logarithm dimensionless and considered that the numbers of the instanton and anti-instanton are the same:…”

Section: Effective Chiral Action From the Instanton Vacuummentioning

confidence: 99%

“…0) have been made already extensively in Refs. [14][15][16][17][18][19][20], in which the finite current-quark mass was explicitly treated [14][15][16][17][18], and meson-loop (ML) corrections showed a sizable modification to the leading N c contribution [19,20]. From these previous works, it also turned out that the ML corrections are crucial in treating the finite current-quark mass.…”

Section: Introductionmentioning

confidence: 96%

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Scalar susceptibility from the instanton vacuum with meson-loop corrections

Nam

2009

Phys. Rev. D

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The scalar susceptibility ( s ) of QCD, which represents the response of the chiral condensate to a small perturbation of explicit chiral-symmetry breaking (m Þ 0), is investigated within the nonlocal chiral quark model (NLQM) based on the instanton vacuum configuration for N f ¼ 2. We also take into account 1=N c meson-loop (ML) corrections including scalar and pseudoscalar mesons. It turns out that the chiral condensate is modified to a large extend by the ML corrections in the vicinity of m ¼ 0, whereas its effect becomes weak beyond m % 100 MeV. As numerical results, we find that s ¼ À0:34 GeV 2 with the ML corrections and 0:18 GeV 2 without it. From these observations, we conclude that the ML corrections play an important role in the presence of finite current-quark mass.

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Section: Effective Chiral Action From the Instanton Vacuummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Scalar susceptibility from the instanton vacuum with meson-loop corrections

Nam

2009

Phys. Rev. D

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“…Thus, we employ the extended effective chiral action developed in Refs. [37][38][39][40] in which the effects of the current quark mass have been explicitly considered in the instanton vacuum. Since the instanton vacuum realizes SB naturally via quark zero modes, it may provide a good framework to study the EM form factor of the pion and kaon, i.e.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic form factors of the pion and kaon from the instanton vacuum

Nam

Kim

2008

Phys. Rev. D

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We investigate the pion and kaon ( þ , K þ , K 0 ) electromagnetic form factors in the spacelike region: Q 2 & 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N c limit. Explicit flavor SU(3) symmetry breaking is taken into account. The nonlocal contributions turn out to be crucial to reproduce the experimental data. While the pion electromagnetic form factor is in good agreement with the data, the kaon one seems underestimated. We also calculate the electromagnetic charge radii for the pion and kaon: hr 2 i þ ¼ 0:455 fm 2 , hr 2 i K þ ¼ 0:534 fm 2 , and hr 2 i K 0 ¼ À0:060 fm 2 without any adjustable free parameter except for the average instanton size and interinstanton distance, and they are compatible with the experimental data.

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“…The presence of the current quark mass also affects the dynamical one, which was studied in Refs. [40,42] in detail. The additional factor f (m f ) describes the m f dependence of the dynamical quark mass, which is defined as [41,45] f…”

Section: Gauged Nonlocal Effective Chiral Action In the Presencementioning

confidence: 99%

“…When the finite current quark mass is considered, one needs to modify the EχA derived by Diakonov and Petrov [27]. The modification was performed by Musakhanov [40][41][42]. In particular, it is essential to include the current quark mass in the EχA, when one deals with properties of the kaon.…”

Section: Introductionmentioning

confidence: 99%

Vector and Axial-vector form factors in radiative kaon decay and flavor SU(3) symmetry breaking

Shim

Kim

2019

Physics Letters B

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We study the vector and axial-vector form factors of radiative kaon decay within the framework of the gauged nonlocal effective chiral action from the instanton vacuum, focusing on the effects of flavor SU(3) symmetry breaking. The general tendency of the results are rather similar to those of radiative pion decays: The nonlocal contributions make the results of the vector form factor increased by about 20 %, whereas they reduce those of the axial-vector form factor by almost 50 %. Suppressing the prefactors consisting of the kaon mass and the pion decay constant, we scrutinize how the kaon form factors undergo changes as the mass of the strange current quark is varied. Those related to the vector and second axial-vector form factors tend to decrease monotonically as the strange quark mass increases, whereas that for the axial-vector form factor decreases. When K → eνγ decay is considered, both the results of the vector and axial-vector form factors at the zero momentum transfer are in good agreement with the experimental data. The results are also compared with those from chiral perturbation theory to p 6 order.Keywords: Radiative kaon decay, vector and axial-vector form factors of the kaon, instanton vacuum *

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Improved effective action for light quarks beyond the chiral limit

Cited by 39 publications

References 13 publications

Scalar susceptibility from the instanton vacuum with meson-loop corrections

Scalar susceptibility from the instanton vacuum with meson-loop corrections

Electromagnetic form factors of the pion and kaon from the instanton vacuum

Vector and Axial-vector form factors in radiative kaon decay and flavor SU(3) symmetry breaking

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