B and D meson decay constants from 2+1 flavor improved staggered simulations

Understand

We give an update on simulation results for the decay constants f_B, f_{B_s}, f_D and f_{D_s}.

• These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity triangle fit.
• The results presented here make use of the MILC (2+1)-flavor asqtad ensembles, with heavy quarks incorporated using the clover action with the Fermilab method.
• Partially quenched, staggered chiral perturbation theory is used to extract the decay constants at the physical point.