Quantitative sum rule analysis of low-temperature spectral functions

Abstract

We analyze QCD and Weinberg-type sum rules in a low-temperature pion gas using vector and axial-vector spectral functions following from the model-independent chiral-mixing scheme. Toward this end we employ recently constructed vacuum spectral functions with ground and first-excited states in both channels and a universal perturbative continuum; they quantitatively describe hadronic tau-decay data and satisfy vacuum sum rules. These features facilitate the implementation of chiral mixing without further assumptions, and lead to in-medium spectral functions which exhibit a mutual tendency of compensating resonance and dip structures, suggestive for an approach toward structureless distributions. In the sum rule analysis, we account for pion mass corrections, which turn out to be significant. While the Weinberg sum rules remain satisfied even at high temperatures, the numerical evaluation of the QCD sum rules for vector and axial-vector channels reveals significant deviations setting in for temperatures beyond ~140 MeV, suggestive of additional physics beyond low-energy chiral pion dynamics.

8 pages, 3 figures

References in corpus (5)

• The chiral and deconfinement aspects of the QCD transition
• Gluon Condensates and m_{c,b} from QCD-Moments and their ratios to Order alpha_s^3 and <G^4>
• Four-quark condensates and chiral symmetry restoration in a resonance gas model
• Sum rule analysis of vector and axial-vector spectral functions with excited states in vacuum
• Vector-axialvector mixing from a chiral effective field theory at finite temperature

Cited by in corpus (10)

• Recent Progress in QCD Condensate Evaluations and Sum Rules
• Is Rho-Meson Melting Compatible with Chiral Restoration?
• In-Medium Spectral Functions of Vector- and Axial-Vector Mesons from the Functional Renormalization Group
• Wilson coefficients and four-quark condensates in QCD sum rules for medium modifications of $D$ mesons
• Electromagnetic effects in the pion dispersion relation at finite temperature
• Massive Yang-Mills for Vector and Axial-Vector Spectral Functions at Finite Temperature
• Chiral-partner D mesons in a heat bath within QCD sum rules
• Weinberg sum rules at finite temperature
• Chiral symmetry aspects in the open charm sector
• Hadronic matter at the edge: A survey of some theoretical approaches to the physics of the QCD phase diagram