We study the correlators of Polyakov loops, and the corresponding gauge
invariant free energy of a static quark-antiquark pair in 2+1 flavor QCD at
finite temperature. Our simulations were carried out on Nt = 6, 8, 10, 12,
16 lattices using a Symanzik improved gauge action and a stout improved
staggered action with physical quark masses. The free energies calculated from
the Polyakov loop correlators are extrapolated to the continuum limit. For the
free energies we use a two step renormalization procedure that only uses data
at finite temperature. We also measure correlators with definite Euclidean time
reversal and charge conjugation symmetry to extract two different screening
masses, one in the magnetic, and one in the electric sector, to distinguish two
different correlation lengths in the full Polyakov loop correlator. This
conference contribution is based on the paper: JHEP 1504 (2015) 138Comment: 7 pages, 4 figures. Talk presented at the 33rd International
Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe
International Conference Center, Kobe, Japa