What happens to the Υ \Upsilon and η b in the quark-gluon plasma? Bottomonium spectral functions from lattice QCD

We study bottomonium spectral functions in the quark-gluon plasma in the Υ and η b channels, using lattice QCD simulations with two flavours of light quark on highly anisotropic lattices. The bottom quark is treated with nonr elativistic QCD (NRQCD). In the temperature range we consider, 0 . 42 ≤ T/T c ≤ 2 . 09, we find that the ground states survive, whereas the excited states are suppressed as the te mperature is increased. The position and width of the ground states are compared to analy tical effective field theory (EFT) predictions. Systematic uncertainties of the maximu m entropy method (MEM), used to construct the spectral functions, are discussed in s ome detail