6 research outputs found
D-meson semileptonic decays to pseudoscalars from four-flavor lattice QCD
We present lattice-QCD calculations of the hadronic form factors for the
semileptonic decays , , and .
Our calculation uses the highly improved staggered quark (HISQ) action for all
valence and sea quarks and includes MILC ensembles with lattice
spacings ranging from fm down to fm. At most lattice
spacings, an ensemble with physical-mass light quarks is included. The HISQ
action allows all the quarks to be treated with the same relativistic
light-quark action, allowing for nonperturbative renormalization using partial
conservation of the vector current. We combine our results with experimental
measurements of the differential decay rates to determine
and This result for is
the most precise to date, with a lattice-QCD error that is, for the first time
for the semileptonic extraction, at the same level as the experimental error.
Using recent measurements from BES III, we also give the first-ever
determination of from . Our results also furnish new
Standard Model calculations of the lepton flavor universality ratios
, , and , which are consistent within with experimental
measurements. Our extractions of and , when combined with
a value for , provide the most precise test of second-row CKM
unitarity, finding agreement with unitarity at the level of one standard
deviation.Comment: 92 page
Form factors for semileptonic B-decays with HISQ light quarks and clover b-quarks in Fermilab interpretation
We compute the vector, scalar, and tensor form factors for the , , and amplitudes, which are needed to describe semileptonic -meson decay rates for both the charged and neutral current cases. We use the highly improved staggered quark (HISQ) action for the sea and light valence quarks. The bottom quark is described by the clover action in the Fermilab interpretation. Simulations are carried out on MILC HISQ ensembles at approximate lattice spacings from fm down to fm. We present blinded preliminary results for the form factors.We compute the vector, scalar, and tensor form factors for the , , and amplitudes, which are needed to describe semileptonic -meson decay rates for both the charged and neutral current cases. We use the highly improved staggered quark (HISQ) action for the sea and light valence quarks. The bottom quark is described by the clover action in the Fermilab interpretation. Simulations are carried out on MILC HISQ ensembles at approximate lattice spacings from fm down to fm. We present blinded preliminary results for the form factors
Semileptonic
We report the status of an ongoing lattice-QCD calculation of form factors for exclusive semileptonic decays of B mesons with both charged currents (B → πlv, Bs → Klv) and neutral currents (B → πl+l-, B → Kl+l-). The results are important for constraining or revealing physics beyond the Standard Model. This work uses MILC’s (2+1 + 1)-flavor ensembles with the HISQ action for the sea and light valence quarks and the clover action in the Fermilab interpretation for the b quark. Simulations are carried out at three lattice spacings down to 0.088 fm, with both physical and unphysical sea-quark masses. We present preliminary results for correlation-function fits
Semileptonic B-meson decays to light pseudoscalar mesons on the HISQ ensembles
We report the status of an ongoing lattice-QCD calculation of form factors for exclusive semileptonic decays of B mesons with both charged currents (B → πlv, Bs → Klv) and neutral currents (B → πl+l-, B → Kl+l-). The results are important for constraining or revealing physics beyond the Standard Model. This work uses MILC’s (2+1 + 1)-flavor ensembles with the HISQ action for the sea and light valence quarks and the clover action in the Fermilab interpretation for the b quark. Simulations are carried out at three lattice spacings down to 0.088 fm, with both physical and unphysical sea-quark masses. We present preliminary results for correlation-function fits