Multilevel algorithms for glueball calculations

by Lorenzo Barca (DESY Zeuthen)

Tuesday 25 Jun 2024, 16:00 → 18:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

Glueballs, predicted by QCD, are states predominantly made of gluons, yet no clear experimental observation has been made since their prediction. Recently, the BESIII collaboration reported the discovery of a pseudoscalar glueball-like particle X(2370), compatible with lattice QCD predictions. Lattice QCD is ideal for investigating these composite states, but challenges such as the signal-to-noise ratio and the analysis with multi-meson interpolating operators hinder comprehensive studies of the glueball spectrum in full QCD.
I will discuss our recent use of the multilevel algorithm to improve the signal-to-noise ratio in pure Yang-Mills theory simulations. The multilevel algorithm enables us to obtain signal at larger distances (up to $\sim$ 0.82 fm) compared to standard algorithms at the same cost, which will be crucial for studies of glueball-charmonium mixing in full QCD.