NeutralBmeson mixings andBmeson decay constants with static heavy and domain-wall light quarks

Abstract

Neutral B meson mixing matrix elements and B meson decay constants are calculated. Static approximation is used for b quark and domain-wall fermion formalism is employed for light quarks. The calculations are carried out on 2 + 1 flavor dynamical ensembles generated by RBC/UKQCD Collaborations with lattice spacings 0.086 fm (a −1 ∼ 2.3 GeV) and 0.11 fm (1.7 GeV), and a fixed physical spatial volume of about (2.7 fm) 3 . In the static quark action, link-smearings are used to improve the signal-to-noise ratio. We employ two kinds of link-smearings, HYP1 and HYP2, and their results are combined in taking the continuum limit. For the matching between the lattice and the continuum theory, one-loop perturbative O(a) improvements are made to reduce discretization errors. As the most important quantity of this work, we obtain SU (3)

CP violation in the Bs0 system

“…dall et al, 2014)), ETMC (Carrasco et al, 2014), the LATTICE 2015 update from the Fermilab-MILC Collaboration (Bouchard et al, 2011) and the LATTICE 2015 update from RBC-UKQCD of (Aoki et al, 2015) -that seem to indicate that f Bs √ B can be determined with an uncertainty as low as 5% in the near future. In most of these works not only the matrix element of Q, but also the full ∆B = 2 operator basis is studied.…”

“…Here the value of V ub is taken from the fit and not from either an inclusive or an exclusive determination. Finally we also present in Table XI a list of additional lattice determinations for f Bs √ B andB S /B, given by HQPCD (LATTICE 2014 update by (Dowdall et al, 2014)), ETMC (Carrasco et al, 2014), the LATTICE 2015 update from the Fermilab-MILC Collaboration (Bouchard et al, 2011) and the LATTICE 2015 update from RBC-UKQCD of (Aoki et al, 2015).…”

“…(54). There is also a large value from RBC-UKQCD presented at LAT-TICE 2015, f Bs √ B = 262 MeV (update of (Aoki et al, 2015)). However, this number is obtained in the static limit and currently missing 1/m b corrections are expected to be very sizable.…”

Summary of Working Group 4 : mixing and mixing-related $CP$ violation in the $B$ system

“…The most precise computation to date for |V td | and |V ts |, or alternatively ∆m d,s , is recently available from the Fermilab/MILC collaboration [46], building on previous results for B mixing matrix elements [47,48,49,50,51,52]. These predictions are achieved via a three flavor lattice QCD calculation for the neutral B mixing hadronic matrix elements, B |O q i |B , with O q i combinations of scalar, pseudoscalar, vector and axial vector four-quark operators as required by the theory of interest.…”

Decay constants $f_B$ and $f_{B_s}$ from HISQ simulations

“…The staggered-fermion local pseudoscalar density does not require renormalization, one of the significant sources of systematic error with other heavy-quark formalisms [5,6,7,8,9]. Compared with HPQCD, our ensembles employ HISQ instead of asqtad sea quarks.…”