Date&Time  Wed Oct 27 2021 (14:00  15:00) 

Speaker  Yu Zhang 
Affiliation  RIKEN RCCS 
Title  Correlated Dirac Eigenvalues and Axial Anomaly in Chiral Symmetric QCD 
Abstract  In this talk I will present the novel relations between the quark mass derivatives [$\partial^n \rho(\lambda,m_l)/\partial m_l^n$] of the Dirac eigenvalue spectrum and the $(n+1)$point correlations among the eigenvalues. Using these relations we present lattice QCD results for $\partial^n \rho(\lambda,m_l)/\partial m_l^n$ ($n=1, 2, 3$) for $m_l$ corresponding to pion masses $m_\pi=16055~$MeV, and at a temperature of about 1.6 times the chiral phase transition temperature. Calculations were carried out using (2+1) flavors of highly improved staggered quarks with the physical value of strange quark mass, three lattice spacings $a=0.12, 0.08, 0.06$~fm. We find that $\rho(\lambda\to0,m_l)$ develops a peaked structure. This peaked structure arises due to nonPoisson correlations within the infrared part of the Dirac eigenvalue spectrum, becomes sharper as $a\to0$, and its amplitude is proportional to $m_l^2$. We demonstrate that this $\rho(\lambda\to0,m_l)$ is responsible for the manifestations of axial anomaly in twopoint correlation functions of light scalar and pseudoscalar mesons. After continuum and chiral extrapolations we find that axial anomaly remains manifested in twopoint correlation functions of scalar and pseudoscalar mesons in the chiral limit. This talk is based on PRL 126 (2021) 082001. 
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