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

Abstract

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 nonrelativistic 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 temperature is increased. The position and width of the ground states are compared to analytical effective field theory (EFT) predictions. Systematic uncertainties of the maximum entropy method (MEM), used to construct the spectral functions, are discussed in some detail.

Ab initiocalculation of finite-temperature charmonium potentials

“…We also hope to extend our work to the potential between heavier quarks using the NRQCD approach [28][29][30].…”

Thermodynamics of strong-interaction matter from lattice QCD

“…235 Treating the bottom quark within the NRQCD framework the fate of bottomonium states has been studied on anisotropic lattices using N f = 2 and 2 + 1 of improved Wilson quarks with m π ≈ 400 MeV and m π ≈ 500 MeV, respectively. 235,[239][240][241][242] Fig. 28 shows the temperature dependence of the Υ (top) and χ b1 (bottom) spectral functions extracted using the MEM.…”

A first look at Bottomonium melting via a stochastic potential

“…A similar type of information is contained in the thermal spectral functions ρ(ω) calculated using the in-medium heavy quarkonium Schroedinger equation [25][26][27], from the T-Matrix approach [28] or directly from lattice QCD [29][30][31][32][33][34][35][36][37]. In vacuum the presence of individual delta peaks clearly outlines possible bound states for the cc pairs to end up in.…”