quark: valence

$B_s$ to $K \ell \nu$ decay from lattice QCD

We use lattice QCD to calculate the form factors f+(q2) and f0(q2) for the semileptonic decay Bs→Kℓν. Our calculation uses six MILC asqtad 2+1 flavor gauge-field ensembles with three lattice spacings. At the smallest and largest lattice spacing the …

$B$- and $D$-meson leptonic decay constants from four-flavor lattice QCD

We calculate the leptonic decay constants of heavy-light pseudoscalar mesons with charm and bottom quarks in lattice quantum chromodynamics on four-flavor QCD gauge-field configurations with dynamical u, d, s, and c quarks. We analyze over twenty …

Short-distance matrix elements for $Dtextasciicircum0$-meson mixing for $N_f=2+1$ lattice QCD

We calculate in three-flavor lattice QCD the short-distance hadronic matrix elements of all five ΔC=2 four-fermion operators that contribute to neutral D-meson mixing both in and beyond the Standard Model. We use the MILC Collaboration’s Nf=2+1 …

$Btextasciicircum0_(s)$-mixing matrix elements from lattice QCD for the Standard Model and beyond

We calculate—for the first time in three-flavor lattice QCD—the hadronic matrix elements of all five local operators that contribute to neutral B0- and Bs-meson mixing in and beyond the Standard Model. We present a complete error budget for each …

$Bto Kltextasciicircum+ltextasciicircum-$ Decay Form Factors from Three-Flavor Lattice QCD

We compute the form factors for the B→Kl+l- semileptonic decay process in lattice QCD using gauge-field ensembles with 2+1 flavors of sea quark, generated by the MILC Collaboration. The ensembles span lattice spacings from 0.12 to 0.045 fm and have …

B→Dℓν form factors at nonzero recoil and textbarV$_b̧$textbar from 2+1-flavor lattice QCD

We present the first unquenched lattice-QCD calculation of the hadronic form factors for the exclusive decay B¯→Dℓν¯ at nonzero recoil. We carry out numerical simulations on 14 ensembles of gauge-field configurations generated with 2+1 flavors of …

$textbarV_ubtextbar$ from $Btopiellnu$ decays and (2+1)-flavor lattice QCD

We present a lattice-QCD calculation of the B→πℓν semileptonic form factors and a new determination of the CKM matrix element textbarVubtextbar. We use the MILC asqtad (2+1)-flavor lattice configurations at four lattice spacings and light-quark …

Update of $textbarV_b̧textbar$ from the $barBto Dtextasciicircum*ellbarnu$ form factor at zero recoil with three-flavor lattice QCD

We compute the zero-recoil form factor for the semileptonic decay $barBtextasciicircum0to Dtextasciicircum*+elltextasciicircum-barnu$ (and modes related by isospin and charge conjugation) using lattice QCD with three flavors of sea quarks. We use an …

Kaon semileptonic vector form factor and determination of textbarV_ustextbar using staggered fermions

Using staggered fermions and twisted boundary conditions, we calculate the K meson semileptonic decay vector form factor at zero momentum transfer. The HISQ formulation is used for the valence quarks, while the sea quarks are simulated with the …