@inproceedings{oai:niigata-u.repo.nii.ac.jp:00031009, author = {Maezawa, Yu and Aoki, S. and Ejiri, S. and Hatsuda, T. and Kanaya, K. and Ohno, H. and Umeda, T. and WHOT-QCD, Collaboration}, book = {PoS - Proceedings of Science, PoS - Proceedings of Science}, issue = {165}, month = {Jul}, note = {The free energy between a static quark and an antiquark is studied by using the color-singlet Polyakov-line correlation at finite temperature. We perform simulations on 323 £12, 10, 8, 6, 4 lattices in the high temperature phase with the RG-improved gluon action and 2+1 flavors of the clover-improvedWilson quark action. Since the simulations are based on the fixed scale approach that the temperature can be varied without changing the spatial volume and renormalization factor, it is possible to investigate temperature dependence of the heavy-quark free energy without any adjustment of the overall constant. We find that, the heavy-quark free energies at short distance converge to the heavy-quark potential evaluated from the Wilson-loop operator at zero temperature, in accordance with the expected insensitivity of short distance physics to the temperature. At long distance, the heavy-quark free energies approach to twice the single-quark free energies, implying that the interaction between heavy quarks is screened. The Debye screening mass obtained from the long range behavior of the heavy-quark free energy is compared with results of the thermal perturbation theory and those of Nf = 2 and Nf = 0 lattice simulations., The XXVII Internaitonal Symposium on Lattice Field Theory, July 26-31, 2009 Peking University, Beijing, China}, pages = {1--7}, publisher = {SISSA}, title = {Heavy-quark free energy at finite temperature with 2+1 flavors of improved Wilson quarks in fixed scale approach}, volume = {LAT2009}, year = {2009} }