theta dependence of SU(N) gauge theories in the presence of a topological term

By Luigi Del Debbio, H. Panagopoulos, Ettore Vicari Supa, S. O. Physics, U. Edinburgh, D. Physics, U. Cyprus, University of Pisa. 2007

223 citations recorded by the source corpus.

Abstract We review results concerning the θ dependence of 4D S U ( N ) gauge theories and QCD, where θ is the coefficient of the CP-violating topological term in the Lagrangian. In particular, we discuss θ dependence in the large- N limit. Most results have been obtained within the lattice formulation of the theory via numerical simulations. We review results at zero and finite temperature. We show that the results support the scenario obtained by general large- N scaling arguments, and in particular the Witten–Veneziano mechanism to explain the U ( 1 ) A problem. We also compare with results obtained by other approaches, especially in the large- N limit, where the issue has been also addressed using, for example, the AdS/CFT correspondence. We discuss issues related to θ dependence in full QCD: the neutron electric dipole moment, the dependence of the topological susceptibility on the quark masses, the U ( 1 ) A symmetry breaking at finite temperature. We also review results in the 2D C P N − 1 model, which is an interesting theoretical laboratory to study issues related to topology. Finally, we discuss the main features of the two-point correlation function of the topological charge density.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/20e278ce5a74338aac0334ba331aa395beaed8f1

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Citations in the corpus

Thermal transport and drag force in improved holographic QCD (2009, result): “In the CP-violating sector, the topological vacuum density tr F F̃ has zero expectation value in the deconfined phase, in agreement with lattice results [48] and large-Nc expectations.”
Holography and thermodynamics of 5D dilaton-gravity (2008, result): “The physics of the transition matches in detail with that of deconfinement of the Yang-Mills theory.”
Resurgence and trans-series in Quantum Field Theory: the $\mathbb{C}{{\mathbb{P}}^{N-1 }}$ model (2012, result): “If we set this as boundary value at N = ∞ for the topological susceptibility, our result provides a prediction for finite values of N , which seems to be in accord with numerical lattice simulations [86].”
Improved holographic Yang–Mills at finite temperature: Comparison with data (2009, result): “This is in agreement with large-Nc arguments and lattice results [21].”
Improved Holographic QCD (2010, result): “In the CP-violating sector, the topological vacuum density TrFF̃ has zero expectation value in the deconfined phase, in agreement with lattice results [21] and large-Nc expectations.”