Axion phenomenology and theta-dependence from Ni-f=2+1 lattice QCD

作者：Bonati Claudio^*; D'Elia Massimo^*; Mariti Marco^*; Martinelli Guido^*; Mesiti Michele^*; Negro Francesco^*; Sanfilippo Francesco^*; Villadoro Giovanni^*

来源：The Journal of High Energy Physics, 2016, 2016(3): 155.

DOI：10.1007/JHEP03(2016)155

• CP violation
• Lattice QCD

We investigate the topological properties of N-f = 2 + 1 QCD with physical quark masses, both at zero and finite temperature. We adopt stout improved staggered fermions and explore a range of lattice spacings a similar to 0.05-0.12 fm. At zero temperature we estimate both finite size and finite cut-off effects, comparing our continuum extrapolated results for the topological susceptibility chi with predictions from chiral perturbation theory. At finite temperature, we explore a region going from T-c up to around 4 T-c, where we provide continuum extrapolated results for the topological susceptibility and for the fourth moment of the topological charge distribution. While the latter converges to the dilute instanton gas prediction the former differs strongly both in the size and in the temperature dependence. This results in a shift of the axion dark matter window of almost one order of magnitude with respect to the instanton computation.

• 出版日期2016-3-22