η′ and η′ masses and decay constants

Gunnar Bali, Sara Collins, Jakob Simeth, M. Della Morte, P. Fritzsch, E. Gámiz Sánchez, C. Pena Ruano
2018 EPJ Web of Conferences  
We present preliminary results for the masses and decay constants of the $\eta$ and $\eta^\prime$ mesons using CLS $N_f = 2+1$ ensembles. One of the major challenges in these calculations are the large statistical fluctuations due to disconnected quark loops. We tackle these by employing a combination of noise reduction techniques which are tuned to minimize the statistical error at a fixed cost. On the analysis side we carefully assess excited states contributions by using a direct fit approach.
more » ... direct fit approach.
doi:10.1051/epjconf/201817505028 fatcat:5njabigomvaudlv7ar6d6lwbdm