Many precision measurements of quarkonium suppression at the LHC, e.g. the nuclear modification factor R_AA of J/Psi, are well described by a multitude of different models . Thus pinpointing the underlying physics is difficult and first principles guidance is needed. In-medium spectral properties, e.g. mass shifts or the broadening of states can help us to understand quarkonium production in a kinetically equilibrated setting. While potential based approaches with lattice input  have been used to estimate such modifications, a direct and quantitative determination from first principles lattice QCD is still outstanding.
Advancing towards this goal we present here a high statistics study of bottomonium and charmonium S-wave and P-wave spectral properties at finite temperature using the effective field theory NRQCD on the lattice. This EFT allows us to capture the physics of quarkonium without modelling assumptions in a realistic thermal QCD medium, described by state-of-the-art lattices of the HotQCD collaboration at almost physical pion mass . The availability of two Bayesian methods for spectral functions (MEM and BR ) makes it possible to thoroughly test the systematic uncertainties of their reconstruction.
Our new lattice QCD correlation functions and reconstructed spectra corroborate a picture of sequential modification of states with respect to their vacuum binding energy. We find that remnant features of the bottomonium S-wave may survive up to T~400MeV, while the P-wave ground state disappears around T~300MeV. The charmonium analysis hints at melting of the P-wave below T~190MeV while some S-wave remnant feature might survive up to T~245MeV.
With the inclusion of charmonium spectra, an extended temperature range and increased statistics by more than an order of magnitude our study provides a coherent picture of in-medium quarkonium modification extending significantly beyond our previous results of Ref. .
 A. Andronic et.al., Eur.Phys.J. C76 (2016) no.3, 107
 Y. Burnier, A.Rothkopf, O. Kaczmarek JHEP 1512 (2015) 101 and arXiv:1606.06211
 A. Bazavov et. al., Phys.Rev. D85 (2012) 054503 and Phys.Rev. D90 (2014) 094503
 Y. Burnier, A. Rothkopf, Phys.Rev.Lett. 111 (2013) 182003
 S. Kim, P. Petreczky, A. Rothkopf, Phys.Rev. D91 (2015) 054511 and arXiv:1512.05289 (QM2015)
|Preferred Track||QCD at High Temperature|