We present results for B(s) and D(s)meson semileptonic decays from ongoing calculations by the Fermilab Lattice and MILC Collaborations. Our calculation employs the highly improved stag gered quark (HISQ) action for both sea and valence quarks and includes several ensembles with physicalmass up, down, strange, and charm quarks and lattice spacings ranging from a ≈ 0.15 fm down to 0.06 fm. At most lattice spacings, an ensemble with physicalmass light quarks is included. The use of the highly improved action, combined with the MILC Collaboration’s gauge ensembles with lattice spacings down to a ≈ 0.042 fm, allows heavy valence quarks to be treated with the same discretization as the light and strange quarks. This unified treatment of the valence quarks allows (in some cases) for absolutely normalized currents, bypassing the need for perturbative matching, which has been a leading source of uncertainty in previous calculations of Bmeson decay form factors by our collaboration. All preliminary formfactor results are blinded.
B and Dmeson leptonic decay constants and quark masses from fourflavor lattice QCD
We describe a recent latticeQCD calculation of the leptonic decay con
stants of heavylight pseudoscalar mesons containing charm and bottom
quarks and of the masses of the up, down, strange, charm, and bottom
quarks. Results for these quantities are of the highest precision to date.
Calculations use 24 isospinsymmetric ensembles of gaugefield configura
tions with six different lattice spacings as small as approximately 0.03 fm
and several values of the light quark masses down to physical values of
the average up and downseaquark masses. We use the highlyimproved
staggered quark (HISQ) formulation for valence and sea quarks, includ
ing the bottom quark. The analysis employs heavyquark effective theory
(HQET). A novel HQET method is used in the determination of the quark
masses.
 Award ID(s):
 1719626
 Publication Date:
 NSFPAR ID:
 10093396
 Journal Name:
 13th Conference on the Intersections of Particle and Nuclear Physics
 Volume:
 arXiv:1810.00250
 Sponsoring Org:
 National Science Foundation
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