B-meson semileptonic decays with highly improved staggered quarks

Abstract

We present an update for results on 𝐵-meson semileptonic decays using the highly improved staggered quark (HISQ) action for both valence and 2+1+1 sea quarks. The use of the highly improved action, combined with the MILC collaboration's gauge ensembles with lattice spacings down to ∼0.03 fm, allows the 𝑏 quark to be treated with the same discretization as the lighter quarks. The talk will focus on updated results for 𝐵 (𝑠) → 𝐷 (𝑠) , 𝐵 (𝑠) → 𝐾 scalar and vector form factors.

Quark flavor physics with lattice QCD

“…At this conference, Andrew Lytle presented preliminary results for the 𝐵 𝑠 → 𝐷 𝑠 form factors using the fully relativistic all-HISQ approach from the Fermilab/MILC collaboration [41], and Benjamin Choi and Seungyeob Jwa from the LANL-SWME collaboration reported on their progress toward a calculation of the 𝐵 → 𝐷 * form factors using the Oktay-Kronfeld action for the heavy quarks on the MILC HISQ ensembles [42,43]. Aurora Melis presented a lattice determination of the susceptibilities that enter in dispersive bounds on 𝑏 → 𝑐 form factors [44].…”

“…Protick Mohanta discussed JLQCD's study of the 𝐵 𝑠 → 𝐾 form factors using the Möbius domain-wall action for all quarks [72]. Andrew Lytle from the Fermilab/MILC collaboration presented preliminary results for the same form factors using an all-HISQ approach [41], while Hwancheol Jeong reported on Fermilab/MILC's calculation of the 𝐵 → 𝜋 and 𝐵 𝑠 → 𝐾 form factors using HISQ light quarks and Fermilab 𝑏 quarks [73]. I gave an update on a nextgeneration determination of the Λ 𝑏 → 𝑝 form factors with domain-wall light quarks and RHQ 𝑏 quarks [62].…”