$B$ and $D$meson leptonic decay constants from fourflavor lattice QCD
Abstract
We calculate the leptonic decay constants of heavylight pseudoscalar mesons with charm and bottom quarks in lattice quantum chromodynamics on fourflavor QCD gaugefield configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We analyze over twenty isospinsymmetric ensembles with six lattice spacings down to $$a\approx 0.03$$~fm and several values of the lightquark mass down to the physical value $$\frac{1}{2}(m_u+m_d)$$. We employ the highlyimproved staggeredquark (HISQ) action for the sea and valence quarks; on the finest lattice spacings, discretization errors are sufficiently small that we can calculate the $B$meson decay constants with the HISQ action for the first time directly at the physical $b$quark mass. We obtain the most precise determinations todate of the $D$ and $B$meson decay constants and their ratios, $$f_{D^+} = 212.6 (0.5)$$~MeV, $$f_{D_s} = 249.8(0.4)$$~MeV, $$f_{D_s}/f_{D^+} = 1.1749(11)$$, $$f_{B^+} = 189.4(1.4)$$~MeV, $$f_{B_s} = 230.7(1.2)$$~MeV, $$f_{B_s}/f_{B^+} = 1.2180(49)$$, where the errors include statistical and all systematic uncertainties. Our results for the $B$meson decay constants are three times more precise than the previous best latticeQCD calculations, and bring the QCD errors in the StandardModel predictions for the rare leptonic decays $$\overline{\mathcal{B}}(B_s \to \mu^+\mu^) = 3.65(11) \times 10^{9}$$, $$\overline{\mathcal{B}}(B^0 \to \mu^+\mu^) = 1.00(3) \times 10^{11}$$, and $$\overline{\mathcal{B}}(B^0 \to \mu^+\mu^)/\overline{\mathcal{B}}(B_s \to \mu^+\mu^) = 0.00264(7)$$ to well below other sources of uncertainty. As a byproduct of our analysis, we also update our previously published results for the lightquarkmass ratios and the scalesetting quantities $$f_{p4s}$$, $$M_{p4s}$$, and $$R_{p4s}$$. We obtain the most precise latticeQCD determination to date of the ratio $$f_{K^+}/f_{\pi^+} = 1.1950(^{+15}_{22})$$~MeV.
 Authors:
 Michigan State U.
 Washington U., St. Louis
 Utah U.
 Fermilab
 Granada U., Theor. Phys. Astrophys.
 Indiana U.
 APS, New York
 TUMIAS, Munich
 Syracuse U.
 RIKEN BNL
 UC, Santa Barbara
 Glasgow U.
 Publication Date:
 Research Org.:
 Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), High Energy Physics (HEP) (SC25)
 OSTI Identifier:
 1423226
 Report Number(s):
 FERMILABPUB17491T; arXiv:1712.09262
1644910
 DOE Contract Number:
 AC0207CH11359
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: TBD
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Citation Formats
Bazavov, A., Bernard, C., Brown, N., Detar, C., ElKhadra, A. X., Gámiz, E., Gottlieb, Steven, Heller, U. M., Komijani, J., Kronfeld, A. S., Laiho, J., Mackenzie, P. B., Neil, E. T., Simone, J. N., Sugar, R. L., Toussaint, D., and Van De Water, R. S.. $B$ and $D$meson leptonic decay constants from fourflavor lattice QCD. United States: N. p., 2017.
Web.
Bazavov, A., Bernard, C., Brown, N., Detar, C., ElKhadra, A. X., Gámiz, E., Gottlieb, Steven, Heller, U. M., Komijani, J., Kronfeld, A. S., Laiho, J., Mackenzie, P. B., Neil, E. T., Simone, J. N., Sugar, R. L., Toussaint, D., & Van De Water, R. S.. $B$ and $D$meson leptonic decay constants from fourflavor lattice QCD. United States.
Bazavov, A., Bernard, C., Brown, N., Detar, C., ElKhadra, A. X., Gámiz, E., Gottlieb, Steven, Heller, U. M., Komijani, J., Kronfeld, A. S., Laiho, J., Mackenzie, P. B., Neil, E. T., Simone, J. N., Sugar, R. L., Toussaint, D., and Van De Water, R. S.. 2017.
"$B$ and $D$meson leptonic decay constants from fourflavor lattice QCD". United States.
doi:. https://www.osti.gov/servlets/purl/1423226.
@article{osti_1423226,
title = {$B$ and $D$meson leptonic decay constants from fourflavor lattice QCD},
author = {Bazavov, A. and Bernard, C. and Brown, N. and Detar, C. and ElKhadra, A. X. and Gámiz, E. and Gottlieb, Steven and Heller, U. M. and Komijani, J. and Kronfeld, A. S. and Laiho, J. and Mackenzie, P. B. and Neil, E. T. and Simone, J. N. and Sugar, R. L. and Toussaint, D. and Van De Water, R. S.},
abstractNote = {We calculate the leptonic decay constants of heavylight pseudoscalar mesons with charm and bottom quarks in lattice quantum chromodynamics on fourflavor QCD gaugefield configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We analyze over twenty isospinsymmetric ensembles with six lattice spacings down to $a\approx 0.03$~fm and several values of the lightquark mass down to the physical value $\frac{1}{2}(m_u+m_d)$. We employ the highlyimproved staggeredquark (HISQ) action for the sea and valence quarks; on the finest lattice spacings, discretization errors are sufficiently small that we can calculate the $B$meson decay constants with the HISQ action for the first time directly at the physical $b$quark mass. We obtain the most precise determinations todate of the $D$ and $B$meson decay constants and their ratios, $f_{D^+} = 212.6 (0.5)$~MeV, $f_{D_s} = 249.8(0.4)$~MeV, $f_{D_s}/f_{D^+} = 1.1749(11)$, $f_{B^+} = 189.4(1.4)$~MeV, $f_{B_s} = 230.7(1.2)$~MeV, $f_{B_s}/f_{B^+} = 1.2180(49)$, where the errors include statistical and all systematic uncertainties. Our results for the $B$meson decay constants are three times more precise than the previous best latticeQCD calculations, and bring the QCD errors in the StandardModel predictions for the rare leptonic decays $\overline{\mathcal{B}}(B_s \to \mu^+\mu^) = 3.65(11) \times 10^{9}$, $\overline{\mathcal{B}}(B^0 \to \mu^+\mu^) = 1.00(3) \times 10^{11}$, and $\overline{\mathcal{B}}(B^0 \to \mu^+\mu^)/\overline{\mathcal{B}}(B_s \to \mu^+\mu^) = 0.00264(7)$ to well below other sources of uncertainty. As a byproduct of our analysis, we also update our previously published results for the lightquarkmass ratios and the scalesetting quantities $f_{p4s}$, $M_{p4s}$, and $R_{p4s}$. We obtain the most precise latticeQCD determination to date of the ratio $f_{K^+}/f_{\pi^+} = 1.1950(^{+15}_{22})$~MeV.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Charmed and light pseudoscalar meson decay constants from fourflavor lattice QCD with physical light quarks
We compute the leptonic decay constants f _{D+}, f _{Ds} , and f _{K+}, and the quarkmass ratios m _{c}=m _{s} and m _{s}=m _{l} in unquenched lattice QCD using the experimentally determined value of f _{π+} for normalization. We use the MILC Highly Improved Staggered Quark (HISQ) ensembles with four dynamical quark flavors  up, down, strange, and charm  and with both physical and unphysical values of the light seaquark masses. The use of physical pions removes the need for a chiral extrapolation, thereby eliminating a significant source of uncertainty in previous calculations. Four different lattice spacing ranging from a ≈ 0:06 fm to 0:15 fm are included in the analysis to control the extrapolation to the continuum limit. Our primary results are f _{D+} = 212:6(0:4)more »Cited by 48 
B and Dmeson decay constants from threeflavor lattice QCD
We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavylight meson correlation functions on the MILC asqtadimproved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence and seaquark masses (down to ~m_s/10) and at three lattice spacings (a ~ 0.15, 0.12, and 0.09 fm) and extrapolate to the physical up and down quark masses and the continuum using expressions derived in heavylight meson staggered chiral perturbation theory. We renormalizemore » 
Bmeson decay constants from 2+1flavor lattice QCD with domainwall light quarks and relativistic heavy quarks
We calculate the Bmeson decay constants f _{B}, f _{B}s, and their ratio in unquenched lattice QCD using domainwall light quarks and relativistic bquarks. We use gaugefield ensembles generated by the RBC and UKQCD collaborations using the domainwall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M _{π} ≈ 290 MeV; this enables us to control the extrapolation to the physical lightquark masses and continuum. For the bquarks we use the anisotropic clover action withmore »