fB and two-scales problems in lattice QCD

B→Dℓνform factors at nonzero recoil and|Vcb|Bailey1, Bazavov2, Bérnard3 et al. 2015Phys. Rev. D274253625View full textAdd to dashboardCite

“…Although this earlier calculation was performed in quenched QCD, and thus is subject to an unquantifiable systematic due to the omission of sea-quark effects, it uses step-scaling [62] to control heavy-quark discretization effects, plus multiple light-quark masses and lattice a +,0 0.01262 (10) spacings to control the mild chiral-continuum extrapolation [13]. Thus it is the best calcu- To obtain |V cb |, we need lattice results for the form factors and experimental values for η EW |V cb |f + (w).…”

Lattice Flavour Physics with an eye to Super-B

“…Several methods have been investigated and adopted so far, that are either based on an effective theory approach or consist in simulating heavy quark masses (m h ) in the charm region (or slightly above) and using some suitable technique to achieve the b-quark region. These are the Tor Vergata step-scaling method [35], which consists in matching several lattice simulations at different volumes and up to the physical b-quark mass on the small volume, the ETMC ratio method [36] based on suitable ratios with exactly known static limit, the HPQCD HISQ simulation [37] [38] the key discretization errors are removed by tuning three parameters combining perturbation theory and experimental inputs. Finally, this year, RBC/UKQCD has formulated the non-perturbatively tuned relativistic heavy-quark action [39].…”

Precision for B-meson matrix elements

“…The continuum limit is reachable by a short, controlled, extrapolation. Starting from this simple idea, two different roads have been taken in the past [17,18,19] and a third one has recently been explored [20].…”