B Meson Decay Constants Using Relativistic Heavy Quarks

Abstract

We present an update on ongoing work to extract pseudoscalar and vector decay constants for𝑠 and 𝐵 ( * ) 𝑐 mesons and determine phenomenologically-interesting ratios such as 𝑓 𝐵 𝑠 / 𝑓 𝐵 or 𝑓 𝐵 * / 𝑓 𝐵 . Our calculation is based on N f = 2 + 1 dynamical flavour gauge field ensembles generated by the RBC/UKQCD collaborations using domain-wall fermions and the Iwasaki gauge action. Using domain-wall light, strange, and charm quarks and relativistic 𝑏 quarks, we obtain results at multiple lattice spacings and valence quark masses.

Quark flavor physics with lattice QCD

“…Quark flavor physics with lattice QCD operators relevant for the theory of heavy-hadron lifetimes [92]. Joshua Lin presented a positionspace renormalization scheme for Δ𝐵 = 2 and Δ𝐵 = 0 four-quark operators in HQET and reported on progress with the matching from this scheme to MS at order 𝛼 𝑠 [93].…”

Heavy flavor physics from lattice QCD

“…Due to the tension between the lattice studies, more independent studies are highly welcome. At this conference, RBC/UKQCD reported on their on-going study of 𝑓 𝐵 * as well as 𝑓 𝐵 𝑐 [71]. They simulate four lattice cutoffs up to 𝑎 −1 ∼ 3.2 GeV and pion masses down to 𝑀 𝜋 ∼ 270 MeV with the RHQ action for bottom quarks.…”

“…Figure 10: Left: effective plot of dimensionless decay amplitudeΨ 𝐵 * /𝑀 3/2 𝐵 𝑠 = 𝑓 𝐵 * √ 𝑀 𝐵 * /𝑀 3/2𝐵 𝑠 (figure from Ref [71]…”