Low energy constants of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>χ</mml:mi><mml:mi>PT</mml:mi></mml:math>from the instanton vacuum model

Goeke, K.; Musakhanov, M.M.; Siddikov, Marat

doi:10.1103/physrevd.76.076007

Cited by 47 publications

(64 citation statements)

References 51 publications

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“…There are different schemes to go beyond the mean-field level [23][24][25][26][27][28][29][30][31][32][33]. One of the most promising ones is based on a strict expansion of the inverse number of quark colors, 1=N c , which is a natural expansion parameter for gauge theories [34].…”

Section: Introductionmentioning

confidence: 99%

Nonlocal Polyakov–Nambu–Jona-Lasinio model beyond mean field and the QCD phase transition

et al. 2011

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A nonlocal chiral quark model is consistently extended beyond mean field using a strict 1=N c expansion scheme. The parameters of the nonlocal model are refitted so that the physical values of the pion mass and the weak pion decay constant are obtained. The size of the 1=N c correction to the quark condensate is carefully studied and compared with the usual local Nambu-Jona-Lasinio model. It is found that even the sign of the corrections can be different. This can be attributed to the mesonic cutoff of the local model. The model is also applied to finite temperature. We find that the 1=N c corrections dominate the melting of the chiral condensate at low temperatures, T & 100 MeV, in agreement with chiral perturbation theory. On the other hand, the relative importance of the 1=N c corrections in the crossover regime depends on the parameter T 0 of the Polyakov-loop potential. For T 0 ¼ 270 MeV, corresponding to a fit of lattice data for pure gluodynamics, the correction terms are large and lead to a lowering of the chiral phase-transition temperature in comparison with the mean-field result. Near the phase transition the 1=N c expansion breaks down and a nonperturbative scheme is needed to include mesonic correlations in that regime. Lowering T 0 leads to a more rapid crossover even at the mean-field level and the unstable region for the 1=N c corrections shrinks. For T 0 & 220 MeV the temperatures of deconfinement and chiral restoration are practically synchronized.

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Section: Introductionmentioning

confidence: 99%

Nonlocal Polyakov–Nambu–Jona-Lasinio model beyond mean field and the QCD phase transition

et al. 2011

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“…The value of C 0 is in (1=3 $ 1=4) for 1= " % 600 MeV, M 0 % ð300 $ 400Þ MeV, and N=V % ð200 $ 260 MeVÞ 4 for vacuum [40]. We choose second-order chiral phase transition for the massless quark and the crossover for the finite quark mass.…”

Section: A Shear Viscosity At Finite Temperaturementioning

confidence: 99%

Shear viscosity of quark matter at finite temperature under an external magnetic field

Nam

Kao

2013

Phys. Rev. D

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We employ the diluted instanton liquid model and the Green-Kubo formula to investigate the shear viscosity of the SU(2) light-flavor quark matter at finite temperature under an external strong magnetic field ejBj $ m 2 . We apply the Schwinger method to calculate the effect of the external magnetic field. We find that the shear viscosity increases as temperature increases even beyond the transition temperature T 0 ¼ 170 MeV if temperature-dependent model parameters are used. On the other hand, with temperature-independent ones the shear viscosity starts to drop when the temperature goes beyond T 0 . Furthermore, we find that the presence of an external magnetic field will reduce the shear viscosity. However, this effect is almost negligible in the chiral-restored phase even for a very strong magnetic field, ejBj % 10 20 gauss. We also compute the ratio of the shear viscosity and the entropy density =s and our results are well compatible with the other theoretical results for a wide temperature range. We also provide the parametrization of the temperature-dependent ratio =s from our numerical result as =s ¼ 0:27 À 0:87=t þ 1:19=t 2 À 0:28=t 3 with t T=T 0 for T ¼ ð100 $ 350Þ MeV when ejBj ¼ 0.

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“…We parametrize them in the form derived in [41][42][43][44][45]. The accuracy of these distribution amplitudes is controlled by 1=N c , where N c is the number of colors, and instanton packing fraction (3) is a universal object, which depends only on the target, but not on the projectile and final states.…”

Section: Diffractive Pion Production On a Protonmentioning

confidence: 99%

Diffractive neutrino production of pions on nuclei: Adler relation within the color-dipole description

2012

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Effects of coherence in neutrino production of pions off nuclei are studied employing the color-dipole representation and path integral technique. If the nucleus remains intact, the process is controlled by the interplay of two length scales. One is related to the pion mass and is quite long (at low Q 2 ), while the other, associated with heavy axial-vector states, is much shorter. The Adler relation is found to be broken at all energies, but especially strongly at * 10 GeV, where the cross section is suppressed by a factor $A À1=3 . On the contrary, in a process where the recoil nucleus breaks up into fragments, the Adler relation turns out to be strongly broken at low energies, where the cross section is enhanced by a factor $A 1=3 , but has a reasonable accuracy at higher energies, where all the coherence length scales become long.

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Low energy constants ofχPTfrom the instanton vacuum model

Cited by 47 publications

References 51 publications

Nonlocal Polyakov–Nambu–Jona-Lasinio model beyond mean field and the QCD phase transition

Nonlocal Polyakov–Nambu–Jona-Lasinio model beyond mean field and the QCD phase transition

Shear viscosity of quark matter at finite temperature under an external magnetic field

Diffractive neutrino production of pions on nuclei: Adler relation within the color-dipole description

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