Marco Mariti

Axion phenomenology and θ-dependence from N f = 2 + 1 lattice QCD

A bstractWe investigate the topological properties of Nf = 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 ∼ 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 χ with predictions from chiral perturbation theory. At finite temperature, we explore a region going from Tc up to around 4 Tc, 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.

Curvature of the chiral pseudocritical line in QCD: Continuum extrapolated results

We determine the curvature of the pseudo-critical line of strong interactions by means of numerical simulations at imaginary chemical potentials. We consider

Anisotropy of the quark-antiquark potential in a magnetic field

N_f=2+1

Curvature of the chiral pseudocritical line in QCD

stout improved staggered fermions with physical quark masses and the tree level Symanzik gauge action, and explore four different sets of lattice spacings, corresponding to

Magnetic susceptibility and equation of state of

N_t = 6,8,10,12

N_f=2+1

, in order to extrapolate results to the continuum limit. Our final estimate is

QCD with physical quark masses

\kappa = 0.0135(20)

Magnetic susceptibility of strongly interacting matter across the deconfinement transition.

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Magnetic field effects on the static quark potential at zero and finite temperature

We investigate the static

Susceptibility of the QCD vacuum to CP-odd electromagnetic background fields.

\overline{Q}Q