2016/06/30 by Peter Petreczky, Hans-Peter Schadler, Sayantan Sharma · 2 citations
Physics and Astronomy · #hep-lat #astro-ph.CO #hep-ph
paper · pdf · doi:10.1016/j.physletb.2016.09.063
published as Phys.Lett. B762 (2016) 498-505 · 19 pages and 7 figures; v2: A new figure, a few references and minor comments added; published version
arxiv created 2016/11/23 · arxiv updated 2016/11/29
We study the topological susceptibility in 2+1 flavor QCD above the chiral crossover transition temperature using Highly Improved Staggered Quark action and several lattice spacings, corresponding to temporal extent of the lattice, Nτ=6,8,10 and 12. We observe very distinct temperature dependences of the topological susceptibility in the ranges above and below 250 MeV. While for temperatures above 250 MeV, the dependence is found to be consistent with dilute instanton gas approximation, at lower temperatures the fall-off of topological susceptibility is milder. We discuss the consequence of our results for cosmology wherein we estimate the bounds on the axion decay constant and the oscillation temperature if indeed the QCD axion is a possible dark matter candidate.