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Abstract
Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.
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Review of lattice results concerning low-energy particle physics: Flavour Lattice Averaging Group (FLAG). THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2017; 77:112. [PMID: 29033670 PMCID: PMC5588406 DOI: 10.1140/epjc/s10052-016-4509-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/11/2016] [Indexed: 06/07/2023]
Abstract
We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor [Formula: see text], arising in the semileptonic [Formula: see text] transition at zero momentum transfer, as well as the decay constant ratio [Formula: see text] and its consequences for the CKM matrix elements [Formula: see text] and [Formula: see text]. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of [Formula: see text] and [Formula: see text] Chiral Perturbation Theory. We review the determination of the [Formula: see text] parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. The latter quantities are an addition compared to the previous review. For the heavy-quark sector, we provide results for [Formula: see text] and [Formula: see text] (also new compared to the previous review), as well as those for D- and B-meson-decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. Finally, we review the status of lattice determinations of the strong coupling constant [Formula: see text].
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B→πll Form Factors for New Physics Searches from Lattice QCD. PHYSICAL REVIEW LETTERS 2015; 115:152002. [PMID: 26550717 DOI: 10.1103/physrevlett.115.152002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 06/05/2023]
Abstract
The rare decay B→πℓ^{+}ℓ^{-} arises from b→d flavor-changing neutral currents and could be sensitive to physics beyond the standard model. Here, we present the first ab initio QCD calculation of the B→π tensor form factor f_{T}. Together with the vector and scalar form factors f_{+} and f_{0} from our companion work [J. A. Bailey et al., Phys. Rev. D 92, 014024 (2015)], these parametrize the hadronic contribution to B→π semileptonic decays in any extension of the standard model. We obtain the total branching ratio BR(B^{+}→π^{+}μ^{+}μ^{-})=20.4(2.1)×10^{-9} in the standard model, which is the most precise theoretical determination to date, and agrees with the recent measurement from the LHCb experiment [R. Aaij et al., J. High Energy Phys. 12 (2012) 125].
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Determination of |V(us)|| from a lattice QCD calculation of the K → πℓν semileptonic form factor with physical quark masses. PHYSICAL REVIEW LETTERS 2014; 112:112001. [PMID: 24702353 DOI: 10.1103/physrevlett.112.112001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Indexed: 06/03/2023]
Abstract
We calculate the kaon semileptonic form factor f+(0) from lattice QCD, working, for the first time, at the physical light-quark masses. We use gauge configurations generated by the MILC Collaboration with Nf = 2 + 1 + 1 flavors of sea quarks, which incorporate the effects of dynamical charm quarks as well as those of up, down, and strange. We employ data at three lattice spacings to extrapolate to the continuum limit. Our result, f+(0) = 0.9704(32), where the error is the total statistical plus systematic uncertainty added in quadrature, is the most precise determination to date. Combining our result with the latest experimental measurements of K semileptonic decays, one obtains the Cabibbo-Kobayashi-Maskawa matrix element |V(us)| = 0.22290(74)(52), where the first error is from f+(0) and the second one is from experiment. In the first-row test of Cabibbo-Kobayashi-Maskawa unitarity, the error stemming from |V(us)| is now comparable to that from |V(ud)|.
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Leptonic-decay-constant ratio f(K+)/f(π+) from lattice QCD with physical light quarks. PHYSICAL REVIEW LETTERS 2013; 110:172003. [PMID: 23679710 DOI: 10.1103/physrevlett.110.172003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Indexed: 06/02/2023]
Abstract
A calculation of the ratio of leptonic decay constants f(K+)/f(π+) makes possible a precise determination of the ratio of Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |V(us)|/|V(ud)| in the standard model, and places a stringent constraint on the scale of new physics that would lead to deviations from unitarity in the first row of the CKM matrix. We compute f(K+)/f(π+) numerically in unquenched lattice QCD using gauge-field ensembles recently generated that include four flavors of dynamical quarks: up, down, strange, and charm. We analyze data at four lattice spacings a ≈ 0.06, 0.09, 0.12, and 0.15 fm with simulated pion masses down to the physical value 135 MeV. We obtain f(K+)/f(π+) = 1.1947(26)(37), where the errors are statistical and total systematic, respectively. This is our first physics result from our N(f) = 2+1+1 ensembles, and the first calculation of f(K+)/f(π+) from lattice-QCD simulations at the physical point. Our result is the most precise lattice-QCD determination of f(K+)/f(π+), with an error comparable to the current world average. When combined with experimental measurements of the leptonic branching fractions, it leads to a precise determination of |V(us)|/|V(ud)| = 0.2309(9)(4) where the errors are theoretical and experimental, respectively.
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Refining new-physics searches in B→Dτν with lattice QCD. PHYSICAL REVIEW LETTERS 2012; 109:071802. [PMID: 23006357 DOI: 10.1103/physrevlett.109.071802] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Indexed: 06/01/2023]
Abstract
The semileptonic decay channel B→Dτν is sensitive to the presence of a scalar current, such as that mediated by a charged-Higgs boson. Recently, the BABAR experiment reported the first observation of the exclusive semileptonic decay B→Dτ(-)ν, finding an approximately 2σ disagreement with the standard-model prediction for the ratio R(D)=BR(B→Dτν)/BR(B→Dℓν), where ℓ = e,μ. We compute this ratio of branching fractions using hadronic form factors computed in unquenched lattice QCD and obtain R(D)=0.316(12)(7), where the errors are statistical and total systematic, respectively. This result is the first standard-model calculation of R(D) from ab initio full QCD. Its error is smaller than that of previous estimates, primarily due to the reduced uncertainty in the scalar form factor f(0)(q(2)). Our determination of R(D) is approximately 1σ higher than previous estimates and, thus, reduces the tension with experiment. We also compute R(D) in models with electrically charged scalar exchange, such as the type-II two-Higgs-doublet model. Once again, our result is consistent with, but approximately 1σ higher than, previous estimates for phenomenologically relevant values of the scalar coupling in the type-II model. As a by-product of our calculation, we also present the standard-model prediction for the longitudinal-polarization ratio P(L)(D)=0.325(4)(3).
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Critical analysis of topological charge determination in the background of center vortices inSU(2)lattice gauge theory. Int J Clin Exp Med 2012. [DOI: 10.1103/physrevd.86.014513] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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9
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QCD thermodynamics with nonzero chemical potential atNt=6and effects from heavy quarks. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.81.114504] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Charmed-meson decay constants in three-flavor lattice QCD. PHYSICAL REVIEW LETTERS 2005; 95:122002. [PMID: 16197067 DOI: 10.1103/physrevlett.95.122002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Indexed: 05/04/2023]
Abstract
We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical and a combination of systematic errors. We also obtain f(Ds)=249+/-3+/-16 MeV for the Ds meson.
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Semileptonic decays of d mesons in three-flavor lattice QCD. PHYSICAL REVIEW LETTERS 2005; 94:011601. [PMID: 15698062 DOI: 10.1103/physrevlett.94.011601] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2004] [Indexed: 05/24/2023]
Abstract
We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties.
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High-precision lattice QCD confronts experiment. PHYSICAL REVIEW LETTERS 2004; 92:022001. [PMID: 14753930 DOI: 10.1103/physrevlett.92.022001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2003] [Indexed: 05/24/2023]
Abstract
The recently developed Symanzik-improved staggered-quark discretization allows unquenched lattice-QCD simulations with much smaller (and more realistic) quark masses than previously possible. To test this formalism, we compare experiment with a variety of nonperturbative calculations in QCD drawn from a restricted set of "gold-plated" quantities. We find agreement to within statistical and systematic errors of 3% or less. We discuss the implications for phenomenology and, in particular, for heavy-quark physics.
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B spectroscopy from NRQCD with dynamical fermions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 54:5777-5794. [PMID: 10021271 DOI: 10.1103/physrevd.54.5777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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15
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Two-flavor staggered fermion thermodynamics at Nt=12. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 54:4585-4594. [PMID: 10021140 DOI: 10.1103/physrevd.54.4585] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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QCD beta function with two flavors of dynamical Wilson fermions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 54:3546-3550. [PMID: 10021025 DOI: 10.1103/physrevd.54.3546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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From spectroscopy to the strong coupling constant with heavy Wilson quarks. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 52:307-319. [PMID: 10019043 DOI: 10.1103/physrevd.52.307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Effects of spatial size, lattice doubling, and source operators on the hadron spectrum with dynamical staggered quarks at 6/g2=5.6. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 49:6026-6038. [PMID: 10016929 DOI: 10.1103/physrevd.49.6026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Hadron spectrum and matrix elements in QCD with dynamical Wilson fermions at 6/g2=5.3. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 49:3546-3562. [PMID: 10017350 DOI: 10.1103/physrevd.49.3546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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21
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Spatial string tension in the deconfined phase of (3+1)-dimensional SU(2) gauge theory. PHYSICAL REVIEW LETTERS 1993; 71:3059-3062. [PMID: 10054847 DOI: 10.1103/physrevlett.71.3059] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Simple hadronic matrix elements with Wilson valence quarks and dynamical staggered fermions at 6/g2=5.6. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1993; 48:370-387. [PMID: 10016090 DOI: 10.1103/physrevd.48.370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Thermodynamics of lattice QCD with two light quarks on a 16(3) x 8 lattice. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1993; 47:3619-3632. [PMID: 10015982 DOI: 10.1103/physrevd.47.3619] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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24
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Comparison of lattice Coulomb-gauge wave functions in the quenched approximation and with dynamical fermions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1993; 47:285-294. [PMID: 10015400 DOI: 10.1103/physrevd.47.285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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25
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Hadron spectrum in QCD with valence Wilson fermions and dynamical staggered fermions at 6/g2=5.6. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 46:2169-2178. [PMID: 10015133 DOI: 10.1103/physrevd.46.2169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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26
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Glueballs and topology in lattice QCD with two light flavors. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1991; 44:2090-2109. [PMID: 10014090 DOI: 10.1103/physrevd.44.2090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Hadron thermodynamics with Wilson quarks. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1991; 43:2396-2400. [PMID: 10013622 DOI: 10.1103/physrevd.43.2396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Hadron spectrum in QCD at 6/g2=5.6. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1990; 42:3794-3818. [PMID: 10012790 DOI: 10.1103/physrevd.42.3794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Overrelaxation and mode coupling in sigma models. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1989; 39:616-622. [PMID: 9959677 DOI: 10.1103/physrevd.39.616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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31
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More on the two-dimensional O(4) sigma model. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1988; 38:3834-3836. [PMID: 9959153 DOI: 10.1103/physrevd.38.3834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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32
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Monte Carlo renormalization-group investigation of the two-dimensional O(4) sigma model. PHYSICAL REVIEW LETTERS 1988; 60:2235-2237. [PMID: 10038298 DOI: 10.1103/physrevlett.60.2235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Observation of the Meissner effect in a lattice Higgs model. PHYSICAL REVIEW LETTERS 1988; 60:1246-1249. [PMID: 10037986 DOI: 10.1103/physrevlett.60.1246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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