Scalar susceptibility from the instanton vacuum with meson-loop corrections

Abstract

The scalar susceptibility (chi_s) of QCD, which represents the response of the chiral condensate to a small perturbation of explicit chiral-symmetry breaking, is investigated within the nonlocal chiral quark model (NLchiQM) based on the instanton vacuum configuration for N_f = 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 = 0, whereas its effect becomes weak beyond m ~ 100 MeV. As numerical results, we find that chi_s = -0.34 GeV^2 with the ML corrections and 0.18 GeV^2 without it, respectively. From these observations, we conclude that the ML corrections play an important role in the presence of finite current-quark mass.

11 pages, 3 figures, accepted for publication in Phys.Rev.D

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Cited by in corpus (8)

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• Fragmentation and quark distribution functions for the pion and kaon with explicit flavor-SU(3)-symmetry breaking
• An effective thermodynamic potential from the instanton with Polyakov-loop contributions
• Generalized form factors and spin structures of the kaon
• Chiral restoration at finite temperature with meson loop corrections
• Heavy pseudoscalar-meson decay constants with strangeness from the extended nonlocal chiral-quark model
• QCD Chiral restoration at finite $T$ under the Magnetic field: Studies based on the instanton vacuum model