Magnetic susceptibility of the QCD vacuum

• Published in: Physics letters. B Vol. 608; no. 1-2; pp. 95 - 106
• Main Authors: Kim, Hyun-Chul, Musakhanov, M., Siddikov, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 17.02.2005; Elsevier Science
• Subjects: Exact sciences and technology; Physics; The physics of elementary particles and fields; Partition functions; Tensor fields; Quark mass; Vector fields; Elementary particle mass; Models; Quarks; Correlation functions; Flavor; Instantons; Quantum chromodynamics; Magnetic susceptibility
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2004.12.080

We investigate the magnetic susceptibility of the QCD vacuum, based on the instanton vacuum. Starting from the instanton liquid model for the instanton vacuum, we derive the light-quark partition function Z[V,T,mˆ] in the presence of the current quark mass mˆ as well as the external Abelian vector and tensor fields. We calculate a two-point correlation function relevant for the magnetic susceptibility and derive it beyond the chiral limit. We obtain for the different flavors the following magnetic susceptibility: χu,d〈iψu,d†ψu,d〉0∼40–45MeV, while χs〈iψs†ψs〉0≃6–10MeV with the quark condensate 〈iψ†ψ〉0.