Search

Predicting the Bs0−B¯s0 width difference ΔΓs relies on the heavy quark expansion and on hadronic matrix elements of ΔB=2 operators. We present the first lattice QCD results for matrix elements of the dimension-7 operators R2,3 and linear combinations R˜2,3 using nonrelativistic QCD for the bottom quark and a highly improved staggered quark (HISQ) action for the strange quark. Computations use MILC Collaboration ensembles of gauge field configurations with 2+1+1 flavors of sea quarks with the HISQ discretization, including lattices with physically light up or down quark masses. We discuss features unique to calculating matrix elements of these operators and analyze uncertainties from series truncation, discretization, and quark mass dependence. Finally we report the first standard model determination of ΔΓs using lattice QCD results for all hadronic matrix elements through O(1/mb). The main result of our calculations yields the 1/mb contribution ΔΓ1/mb=−0.022(10) ps−1. Adding this to the leading order contribution, the standard model prediction is ΔΓs=0.092(14) ps−1.

We calculate the bag parameters for neutral $B$-meson mixing in and beyond the Standard Model, in full four-flavour lattice QCD for the first time. We work on gluon field configurations that include the effect of $u$, $d$, $s$ and $c$ sea quarks with the Highly Improved Staggered Quark (HISQ) action at three values of the lattice spacing and with three $u/d$ quark masses going down to the physical value. The valence $b$ quarks use the improved NRQCD action and the valence light quarks, the HISQ action. Our analysis was blinded. Our results for the bag parameters for all five operators are the most accurate to date. For the Standard Model operator between $B_s$ and $B_d$ mesons we find: $\hat{B}_{B_s}=1.232(53)$, $\hat{B}_{B_d}=1.222(61)$. Combining our results with lattice QCD calculations of the decay constants using HISQ quarks from the Fermilab/MILC collaboration and with experimental values for $B_s$ and $B_d$ oscillation frequencies allows determination of the CKM elements $V_{ts}$ and $V_{td}$. We find $V_{ts} = 0.04189(93)$, $V_{td} = 0.00867(23)$ and $V_{ts}/V_{td} = 0.2071(27)$. Our results agree well (within $2\sigma$) with values determined from CKM unitarity constraints based on tree-level processes (only). Using a ratio to $\Delta M$ in which CKM elements cancel in the Standard Model, we determine the branching fractions ${\text{Br}}(B_s\rightarrow \mu^+\mu^-) = 3.81(18) \times 10^{-9}$ and ${\text{Br}}(B_d\rightarrow \mu^+\mu^-) = 1.031(54) \times 10^{-10}$. We also give results for matrix elements of the operators $R_0$, $R_1$ and $\tilde{R}_1$ that contribute to neutral $B$-meson width differences., Comment: 27 pages, 16 figures. Slight changes to text to clarify arguments. Updated Figure 10. Version accepted by Physical Review D

cd. autorów: L. Cao48,‡, G. Caria145,‡, G. Casarosa57,‡, C. Cecchi56,‡,D. Cˇ ervenkov10,‡,M.-C. Chang22,‡, P. Chang92,‡, R. Cheaib146,‡, V. Chekelian83,‡, Y. Chen154,‡, B. G. Cheon28,‡, K. Chilikin77,‡, K. Cho70,‡, J. Choi14,‡, S.-K. Choi27,‡, S. Choudhury35,‡, D. Cinabro170,‡, L. M. Cremaldi146,‡, D. Cuesta47,‡, S. Cunliffe16,‡, N. Dash33,‡, E. de la Cruz Burelo9,‡, E. de Lucia52,‡, G. De Nardo54,‡, †Editor. ‡Belle II Collaborator. §Theory or external contributing author. M. De Nuccio16,‡, G. De Pietro59,‡, A. De Yta Hernandez9,‡, B. Deschamps129,‡, M. Destefanis60,‡, S. Dey116,‡, F.Di Capua54,‡, S.Di Carlo75,‡, J. Dingfelder129,‡, Z. Doležal10,‡, I. Domínguez Jiménez125,‡, T.V. Dong30,26,‡, D. Dossett145,‡, S. Duell129,‡, S. Eidelman6,96,77,‡, D. Epifanov6,96,‡, J. E. Fast100,‡, T. Ferber16,‡, S. Fiore18,‡, A. Fodor85,‡, F. Forti57,‡, A. Frey24,‡, O. Frost16,‡, B. G. Fulsom100,‡, M. Gabriel83,‡, N. Gabyshev6,96,‡, E. Ganiev61,‡, X. Gao3,‡, B. Gao23,‡, R. Garg101,‡, A. Garmash6,96,‡, V. Gaur169,‡, A. Gaz90,‡, T. Geßler65,‡, U. Gebauer24,‡, M. Gelb48,‡, A. Gellrich16,‡, D. Getzkow65,‡, R. Giordano54,‡, A. Giri35,‡, A. Glazov16,‡, B. Gobbo61,‡, R. Godang157,‡, O. Gogota110,‡, P. Goldenzweig48,‡, B. Golob141,109,‡,W. Gradl63,‡, E. Graziani59,‡, M. Greco60,‡, D. Greenwald114,‡, S. Gribanov6,96,‡, Y. Guan17,‡, E. Guido60,‡, A. Guo41,‡, S. Halder111,‡, K. Hara30,26,‡, O. Hartbrich138,‡, T. Hauth48,‡, K. Hayasaka94,‡, H. Hayashii91,‡, C. Hearty130,‡, I. Heredia De La Cruz9,‡, M. Hernandez Villanueva9,‡, A. Hershenhorn130,‡, T. Higuchi66,‡,M. Hoek63,‡, S. Hollitt124,‡, N. T. HongVan44,‡, C.-L. Hsu160,‡, Y. Hu41,‡, K. Huang92,‡, T. Iijima89,90,‡, K. Inami90,‡, G. Inguglia40,‡,A. Ishikawa119,‡, R. Itoh30,26,‡, Y. Iwasaki30,‡, M. Iwasaki97,‡, P. Jackson124,‡, W. W. Jacobs37,‡, I. Jaegle137,‡, H. B. Jeon73,‡, X. Ji41,‡, S. Jia3,‡,Y. Jin162,‡, C. Joo66,‡,M. Künzel16,‡, I. Kadenko110,‡, J. Kahn78,‡, H. Kakuno121,‡, A. B. Kaliyar36,‡, J. Kandra10,‡, K. H. Kang73,‡, Y. Kato90,‡, T. Kawasaki68,‡, C. Ketter138,‡, M. Khasmidatul143,‡, H. Kichimi30,‡, J. B. Kim71,‡, K. T. Kim71,‡, H. J. Kim73,‡, D.Y. Kim108,‡, K. Kim172,‡, Y. Kim172,‡, T. D. Kimmel169,‡, H. Kindo30,26,‡, K. Kinoshita135,‡, T. Konno68,‡, A. Korobov6,96,‡, S. Korpar144,109,‡, D. Kotchetkov138,‡, R. Kowalewski165,‡, P. Križan141,109,‡, R. Kroeger146,‡, J.-F. Krohn145,‡, P. Krokovny6,96,‡, W. Kuehn65,‡, T. Kuhr78,‡, R. Kulasiri67,‡, M. Kumar81,‡, R. Kumar101,‡, T. Kumita121,‡, A. Kuzmin6,96,‡, Y.-J. Kwon172,‡, S. Lacaprara55,‡, Y.-T. Lai30,‡, K. Lalwani81,‡, J. S. Lange65,‡, S. C. Lee73,‡, J.Y. Lee106,‡, P. Leitl83,‡, D. Levit114,‡, S. Levonian16,‡, S. Li3,‡, L. K. Li41,‡, Y. Li41,‡,Y. B. Li103,‡, Q. Li103,‡, L. Li Gioi83,‡, J. Libby36,‡, Z. Liptak138,‡, D. Liventsev169,‡, S. Longo165,‡, A. Loos158,‡, G. Lopez Castro9,‡, M. Lubej109,‡, T. Lueck57,‡, F. Luetticke129,‡, T. Luo23,‡, F. Müller16,‡, Th. Müller48,‡, C. MacQueen145,‡, Y. Maeda90,‡, M. Maggiora60,‡, S. Maity33,‡, E. Manoni56,‡, S. Marcello60,‡, C. Marinas129,‡, M. Martinez Hernandez4,‡, A. Martini59,‡, D. Matvienko6,96,77,‡, J. A. McKenna130,‡, F. Meier160,‡, M. Merola54,‡, F. Metzner48,‡, C. Miller165,‡, K. Miyabayashi91,‡, H. Miyake30,26,‡, H. Miyata94,‡, R. Mizuk77,88,87,‡, G. B. Mohanty111,163,‡, H. K. Moon71,‡, T. Moon106,‡,A. Morda55,‡, T. Morii66,‡, M. Mrvar109,‡, G. Muroyama90,‡, R. Mussa60,‡, I. Nakamura30,26,‡, T. Nakano99,‡, M. Nakao30,26,‡, H. Nakayama30,26,‡, H. Nakazawa92,‡, T. Nanut109,‡, M. Naruki72,‡, K. J. Nath34,‡, M. Nayak116,‡, N. Nellikunnummel151,‡, D. Neverov90,‡, C. Niebuhr16,‡, J. Ninkovic84,‡, S. Nishida30,26,‡, K. Nishimura138,‡, M. Nouxman143,‡, G. Nowak93,‡, K. Ogawa94,‡, Y. Onishchuk110,‡, H. Ono94,‡, Y. Onuki162,‡, P. Pakhlov77,88,‡, G. Pakhlova87,‡, B. Pal5,‡, E. Paoloni57,‡, H. Park73,‡, C.-S. Park172,‡, B. Paschen129,‡, A. Passeri59,‡, S. Paul114,‡, T. K. Pedlar80,‡, M. Perelló46,‡, I. M. Peruzzi52,‡, R. Pestotnik109,‡, L. E. Piilonen169,‡, L. Podesta Lerma125,‡, V. Popov87,‡, K. Prasanth111,‡, E. Prencipe21,‡, M. Prim48,‡, M. V. Purohit158,‡, A. Rabusov114,‡, R. Rasheed47,‡, S. Reiter65,‡, M. Remnev6,96,‡, P. K. Resmi36,‡, I. Ripp-Baudot47,‡, M. Ritter78,‡, M. Ritzert139,‡, G. Rizzo57,‡, L. Rizzuto141,109,‡, S. H. Robertson85,‡, D. Rodriguez Perez125,‡, J. M. Roney165,‡, C. Rosenfeld158,‡, A. Rostomyan16,‡, N. Rout36,‡, S. Rummel78,‡, G. Russo54,‡, D. Sahoo111,‡, Y. Sakai30,26,‡, M. Salehi143,78,‡, D. A. Sanders146,‡, S. Sandilya135,‡, A. Sangal135,‡, L. Santelj47,‡, J. Sasaki162,‡, Y. Sato30,‡, V. Savinov151,‡, B. Scavino63,‡, M. Schram100,‡, H. Schreeck24,‡, J. Schueler138,‡,C. Schwanda40,‡,A. J. Schwartz135,‡,R.M. Seddon85,‡,Y. Seino94,‡, K. Senyo171,‡, O. Seon90,‡, I. S. Seong138,‡, M. E. Sevior145,‡, C. Sfienti63,‡, M. Shapkin38,‡, C. P. Shen3,‡,M. Shimomura91,‡, J.-G. Shiu92,‡, B. Shwartz6,96,‡,A. Sibidanov165,‡, F. Simon83,113,‡, J. B. Singh101,‡, R. Sinha42,‡, S. Skambraks83,‡, K. Smith145,‡, R. J. Sobie165,‡, A. Soffer116,‡, A. Sokolov38,‡, E. Solovieva77,87,‡, B. Spruck63,‡, S. Staniˇc149,‡, M. Stariˇc109,‡, N. Starinsky147,‡, U. Stolzenberg24,‡, Z. Stottler169,‡, R. Stroili55,‡, J. F. Strube100,‡, J. Stypula93,‡, M. Sumihama25,‡, K. Sumisawa30,26,‡, T. Sumiyoshi121,‡, D. Summers146,‡, W. Sutcliffe48,‡, S. Y. Suzuki30,26,‡, M. Tabata13,‡, M. Takahashi16,‡, M. Takizawa107,‡, U. Tamponi60,‡, J. Tan145,‡, S. Tanaka30,26,‡, K. Tanida2,‡, N. Taniguchi30,‡, Y. Tao137,‡, P. Taras147,‡, G. Tejeda Munoz4,‡, F. Tenchini16,‡, U. Tippawan12,‡, E. Torassa55,‡, K. Trabelsi30,26,‡, T. Tsuboyama30,26,‡, M. Uchida120,‡, S. Uehara30,26,‡, T. Uglov77,87,‡, Y. Unno28,‡, S. Uno30,26,‡, Y. Ushiroda30,26,162,‡, Y. Usov6,96,‡, S. E. Vahsen138,‡, R. van Tonder48,‡, G. Varner138,‡, K. E. Varvell160,‡, A. Vinokurova6,96,‡, L.Vitale61,‡,M.Vos46,‡,A.Vossen17,‡,E.Waheed145,‡,H.Wakeling85,‡,K.Wan162,‡, M.-Z.Wang92,‡, X. L. Wang23,‡, B. Wang135,‡, A. Warburton85,‡, J. Webb145,‡, S. Wehle16,‡, C. Wessel129,‡, J. Wiechczynski93,‡, P. Wieduwilt24,‡, E. Won71,‡, Q. Xu41,‡, X. Xu41,‡, B. D. Yabsley160,‡, S. Yamada30,‡, H. Yamamoto119,‡, W. Yan3,‡, W. Yan154,‡, S. B. Yang71,‡, H. Ye16,‡, I. Yeo70,‡, J. H. Yin41,‡, M. Yonenaga121,‡, T. Yoshinobu94,‡, W. Yuan55,‡, C. Z. Yuan41,‡, Y. Yusa94,‡, S. Zakharov77,87,‡, L. Zani57,‡, M. Zeyrek86,‡, J. Zhang41,‡,Y. Zhang23,‡,Y. Zhang154,‡, X. Zhou3,‡, V. Zhukova77,‡, V. Zhulanov6,96,‡, and A. Zupanc141,109,‡ †Editor. ‡Belle II Collaborator. §Theory or external contributing author., "The Belle II Theory Interface Platform (B2TiP) was created as a physics prospects working group of the Belle II collaboration in June 2014. It offered a platform where theorists and experimentalists could work together to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, τ , quarkonium physics, electroweak precision measurements, and dark sector searches. It is composed of nine working groups (WGs), which 6/654 Downloaded from https://academic.oup.com/ptep/article-abstract/2019/12/123C01/5685006 by Uniwersytet Slaski Biblioteka Glowna user on 20 February 2020 PTEP 2019, 123C01 E. Kou et al. are coordinated by teams of theory and experiment conveners: WG1, Semileptonic and leptonic B Decays; WG2, Radiative and Electroweak Penguins; WG3, φ1 and φ2 (Time-Dependent CP Violation) Measurements; WG4, φ3 Measurement; WG5, Charmless Hadronic B Decay; WG6, Charm; WG7, Quarkonium(-like); WG8, τ and Low-Multiplicity Processes; WG9, New Physics. We organized workshops twice a year from 2014 until 2016, which moved from KEK in Japan to Europe and the Americas, gathering experts in the respective fields for discussions with Belle II members. One of the goals for B2TiP was to propose so-called “golden and silver channels”: we asked each working group to choose, among numerous possible measurements, those that would have the highest potential impact and to focus on them for the writeup. Theorists scrutinized the role of those measurements in terms of understanding the theory behind them, and estimated the theoretical uncertainties now achievable as well as prospects for the future. For flavor physics, having tight control of hadronic uncertainties is one of the most crucial aspects in the field, and this is considered an important criterion in determining the golden or silver channels. Experimentalists, on the other hand, investigated the expected improvements with data from Belle II. For the channels where the errors are dominated by statistical uncertainties, or where systematic errors are reducible, the errors can decrease rapidly as more data becomes available. The impact of the upgraded performance from Belle II is a crucial element in reducing the uncertainties: we therefore include the latest available studies of the detector efficiency using Monte Carlo simulated events.We list the golden and silver channel table in the introductory chapter, as a guide for the chapters that follow. This book is not a collection of reports based on talks given at the workshops. The working group conveners endeavored to construct a coherent document that can be used by Belle II collaborators, and others in the field of flavor physics, as a reference. Two books of a similar type have been produced in the past: The BaBar Book [1] and The Physics of the B Factories [2]. In order to avoid too much repetition with respect to those references, we refer to them wherever possible for introductory material. We would like to thank the section editors and contributing authors for the many stimulating discussions and their tremendous efforts in bringing the book together." (Preface)

We present a lattice quantum chromodynamics determination of the ratio of the scalar and vector form factors for two semileptonic decays of the ${B}_{s}$ meson: ${B}_{s}\ensuremath{\rightarrow}K\ensuremath{\ell}\ensuremath{\nu}$ and ${B}_{s}\ensuremath{\rightarrow}{D}_{s}\ensuremath{\ell}\ensuremath{\nu}$. In conjunction with future experimental data, our results for these correlated form factors will provide a new method to extract $|{V}_{ub}/{V}_{cb}|$, which may elucidate the current tension between exclusive and inclusive determinations of these Cabibbo-Kobayashi-Maskawa mixing matrix parameters. In addition to the form factor results, we determine the ratio of the differential decay rates, and forward-backward and polarization asymmetries, for the two decays.

We present lattice QCD results for the matrix elements of $R_2$ and other dimension-7, $\Delta B = 2$ operators relevant for calculations of $\Delta \Gamma_s$, the $B_s-\bar{B}_s$ width difference. We have computed correlation functions using 5 ensembles of the MILC Collaboration's 2+1+1-flavour gauge field configurations, spanning 3 lattice spacings and light sea quarks masses down to the physical point. The HISQ action is used for the valence strange quarks, and the NRQCD action is used for the bottom quarks. Once our analysis is complete, the theoretical uncertainty in the Standard Model prediction for $\Delta \Gamma_s$ will be substantially reduced., Comment: 8 pages. To appear in the Proceedings of the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spain

We present a lattice quantum chromodynamics determination of the scalar and vector form factors for the ${B}_{s}\ensuremath{\rightarrow}{D}_{s}\ensuremath{\ell}\ensuremath{\nu}$ decay over the full physical range of momentum transfer. In conjunction with future experimental data, our results will provide a new method to extract $|{V}_{cb}|$, which may elucidate the current tension between exclusive and inclusive determinations of this parameter. Combining the form factor results at nonzero recoil with recent HPQCD results for the $B\ensuremath{\rightarrow}D\ensuremath{\ell}\ensuremath{\nu}$ form factors, we determine the ratios ${f}_{0}^{{B}_{s}\ensuremath{\rightarrow}{D}_{s}}({M}_{\ensuremath{\pi}}^{2})/{f}_{0}^{B\ensuremath{\rightarrow}D}({M}_{K}^{2})=1.000(62)$ and ${f}_{0}^{{B}_{s}\ensuremath{\rightarrow}{D}_{s}}({M}_{\ensuremath{\pi}}^{2})/{f}_{0}^{B\ensuremath{\rightarrow}D}({M}_{\ensuremath{\pi}}^{2})=1.006(62)$. These results give the fragmentation fraction ratios ${f}_{s}/{f}_{d}=0.310(30{)}_{\text{stat}}(21{)}_{\text{syst}}(6{)}_{\text{theor}}(38{)}_{\text{latt}}$ and ${f}_{s}/{f}_{d}=\phantom{\rule{0ex}{0ex}}0.307(16{)}_{\text{stat}}(21{)}_{\text{syst}}(23{)}_{\text{theor}}(44{)}_{\text{latt}}$, respectively. The fragmentation fraction ratio is an important ingredient in experimental determinations of ${B}_{s}$ meson branching fractions at hadron colliders, in particular for the rare decay $\mathcal{B}({B}_{s}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$. In addition to the form factor results, we make the first prediction of the branching fraction ratio $R({D}_{s})=\mathcal{B}({B}_{s}\ensuremath{\rightarrow}{D}_{s}\ensuremath{\tau}\ensuremath{\nu})/\mathcal{B}({B}_{s}\ensuremath{\rightarrow}{D}_{s}\ensuremath{\ell}\ensuremath{\nu})=0.301(6)$, where $\ensuremath{\ell}$ is an electron or muon. Current experimental measurements of the corresponding ratio for the semileptonic decays of $B$ mesons disagree with Standard Model expectations at the level of nearly four standard deviations. Future experimental measurements of $R({D}_{s})$ may help understand this discrepancy.

We present a calculation of the form factors, $f_0$ and $f_+$, for the $B_{(s)} \to D_{(s)}$ semileptonic decays. Our work uses the MILC $n_f=2+1$ AsqTad configurations with NRQCD and HISQ valence quarks at four values of the momentum transfer $q^2$. We provide results for the chiral-continuum extrapolations of the scalar and vector form factors.

We present a lattice QCD calculation of the $B\ensuremath{\rightarrow}Dl\ensuremath{\nu}$ semileptonic decay form factors ${f}_{+}({q}^{2})$ and ${f}_{0}({q}^{2})$ for the entire physical ${q}^{2}$ range. Nonrelativistic QCD bottom quarks and highly improved staggered quark charm and light quarks are employed together with ${N}_{f}=2+1$ MILC gauge configurations. A joint fit to our lattice and BABAR experimental data allows an extraction of the Cabibbo-Kobayashi-Maskawa matrix element $|{V}_{cb}|$. We also determine the phenomenologically interesting ratio $R(D)=\mathcal{B}(B\ensuremath{\rightarrow}D\ensuremath{\tau}{\ensuremath{\nu}}_{\ensuremath{\tau}})/\mathcal{B}(B\ensuremath{\rightarrow}Dl{\ensuremath{\nu}}_{l})$ ($l=e,\ensuremath{\mu}$). We find $|{V}_{cb}{|}_{\text{excl}}^{B\ensuremath{\rightarrow}D}=0.0402(17)(13)$, where the first error consists of the lattice simulation errors and the experimental statistical error and the second error is the experimental systematic error. For the branching fraction ratio we find $R(D)=0.300(8)$.

We report the first lattice QCD calculation of the form factors for the standard model tree-level decay B s → K l ν . In combination with future measurement, this calculation will provide an alternative exclusive semileptonic determination of | V u b | . We compare our results with previous model calculations, make predictions for differential decay rates and branching fractions, and predict the ratio of differential branching fractions between B s → K τ ν and B s → K μ ν . We also present standard model predictions for differential decay rate forward-backward asymmetries and polarization fractions and calculate potentially useful ratios of B s → K form factors with those of the fictitious B s → η s decay. Our lattice simulations utilize nonrelativistic QCD b and highly improved staggered light quarks on a subset of the MILC Collaboration 2 + 1 asqtad gauge configurations, including two lattice spacings and a range of light quark masses.

We match continuum and lattice heavy-light four-fermion operators at one loop in perturbation theory. For the heavy quarks we use nonrelativistic QCD and for the massless light quarks the highly improved staggered quark action. We include the full set of $\Delta B=2$ operators relevant to neutral $B$ mixing both within and beyond the Standard Model and match through order $\alpha_s$, $\Lambda_{\mathrm{QCD}}/M_b$, and $\alpha_s/(aM_b)$., Comment: 13 pages, 10 figures. Version accepted by Phys. Rev. D: one diagram added (Fig.4) and text updated accordingly. Typographic errors corrected

We present a quenched lattice calculation of heavy-light meson decay constants, using non-relativistic (NRQCD) heavy quarks in the mass region of the $b$ quark and heavier, and clover-improved light quarks. The NRQCD Hamiltonian and the heavy-light current include the corrections at first order in the expansion in the inverse heavy quark mass. We study the dependence of the decay constants on the heavy meson mass $M$, for light quarks with the tree level ($c_{SW}$ = 1), as well as the tadpole improved clover coefficient. We compare decay constants from NRQCD with results from clover ($c_{SW}=1$) heavy quarks. Having calculated the current renormalisation constant $Z_A$ in one-loop perturbation theory, we demonstrate how the heavy mass dependence of the pseudoscalar decay constants changes after renormalisation. For the first time, we quote a result for $f_B$ from NRQCD including the full one-loop matching factors at $O(\alpha/M)$., Comment: 45 pages, latex, 24 postscript figures

We present a new determination of the strong coupling constant from lattice QCD simulations. We use four different short-distance quantities to obtain the coupling, three different (infrared) meson splittings to tune the simulation parameters, and a wide range of lattice spacings, quark masses, and lattice volumes to test for systematic errors. Our final result consists of ten different determinations of $\alpha^{(3)}_{P}(8.2 GeV)$, which agree well with each other and with our previous results. The most accurate of these, when evolved perturbatively to the $Z^0$ mass, gives $\alpha^{(5)}_{\msbar}(M_Z) = .1174(24)$. We compare our results with those obtained from other recent lattice simulations.

We present a lattice investigation of the heavy-light meson decay constants using Wilson light quarks and NRQCD heavy quarks, partially including the effects of dynamical sea quarks. We calculate the pseudoscalar and vector decay constants over a wide range in heavy quark mass and are able to perform a detailed analysis of heavy quark symmetry. We find consistency between the extrapolation of the NRQCD results and the static case, as expected. We find the slope of the decay constants with $1/M$ is significantly larger than naive expectations and the results of previous lattice calculations. For the first time we extract the non-perturbative coefficients of the slope arising from the $O(1/M)$ heavy quark interactions separately and show the kinetic energy of the heavy quark is dominant and responsible for the large slope. In addition, we find that significant systematic errors remain in the decay constant extracted around the $B$ meson mass due to truncating the NRQCD series at $O(1/M)$. We estimate the higher order contributions to $f_B$ are approximately $20\%$; roughly the same size as the systematic errors introduced by using the Wilson action for light quarks., Comment: 30 pages, Latex, 14 postscript figures

Recent results in Quarkonia are reviewed, including updates on spectroscopy and $\alpha_s$, and a first look at quarkonium annihilation decays., Comment: Talk presented at LATTICE96(heavy quarks), 7 LaTeX pages plus 2 postscript figures, uses espcrc2.sty

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and Bs decay constants and B -> pi l nu form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements., Contributed to the Proceedings of American Physical Society's 2004 Meeting of the Division of Particles and Fields (DPF2004), Riverside, CA, 26-31 August 2004. 3 pages

We compare calculations of B_K with improved staggered quarks (HYP, Asqtad) and demonstrate the improved scaling behaviour that this gives rise to over previous calculations with unimproved staggered quarks. This enables us to perform the calculation of B_K on the MILC dynamical configurations (n_f=2+1), for which we give preliminary results., Comment: 3 pages, 3 figures. Talk presented at Lattice 2004(weak), Fermilab, June 21-26, 2004

Semileptonic, B --> pi l,nu, decays are studied on the MILC dynamical configurations using NRQCD heavy and Asqtad light quarks. We work with light valence quark masses ranging between m_s and m_s/8. Preliminary simple linear chiral extrapolations have been carried out for form factors f_para and f_perp at fixed E_pi. The chirally extrapolated results for the form factors f_+(q^2) and f_0(q^2) are then fit to the Becirevic-Kaidalov (BK) ansatz. Preliminary estimates of the CKM matrix element |V_{ub}| are presented based on the recently published branching fractions for B exclusive semileptonic decays by the CLEO collaboration.

Calculations of B leptonic decays and B- bar B mixing using NRQCD heavy and Asqtad light valence quarks on the MILC dynamical configurations are described. Smearing has been implemented to substantially reduce the statistical errors of the matrix elements needed for the determination of f_B. The four-fermion matrix elements needed for the determination of f_{B_s}^2B_{B_s} have been calculated and a preliminary result is given.

We calculate, for the first time using unquenched lattice QCD form factors, the standard model differential branching fractions dB/dq2(B→Kl(+)l(-)) for l=e, μ, τ and compare with experimental measurements by Belle, BABAR, CDF, and LHCb. We report on B(B→Kl(+)l(-)) in q2 bins used by experiment and predict B(B→Kτ(+)τ(-))=(1.41±0.15)×10(-7). We also calculate the ratio of branching fractions R(e)(μ)=1.00029(69) and predict R(l)(τ)=1.176(40), for l=e, μ. Finally, we calculate the "flat term" in the angular distribution of the differential decay rate F(H)(e,μ,τ) in experimentally motivated q2 bins.

We calculate, for the first time using unquenched lattice QCD, form factors for the rare decay B→Kl+l− in and beyond the Standard Model. Our lattice QCD calculation utilizes a nonrelativistic QCD formulation for the b valence quarks and the highly improved staggered quark formulation for the light valence quarks. We employ the MILC 2+1 asqtad ensembles. The form factor results, based on the z expansion, are valid over the full kinematic range of q2. We construct the ratios f0/f+ and fT/f+, which are useful in constraining new physics and verifying effective theory form factor symmetry relations. We also discuss the calculation of Standard Model observables.

TheB andBs decay constants are key hadronic parameters in the Standard Model (SM) rate for B(s)! + and B=Bs oscillations, with the B meson decay constant also determining the rate for B! . The combination of experiment and theory for these processes provides important constraints on CKM unitarity [1] and the search for new physics, but the strength of the constraints is typically limited by the errors on the hadronic parameters. The decay constants can only be determined accurately from lattice QCD calculations. Several methods have been developed for this [2], with errors decreasing over the years as calculations have improved. Here we provide a step change in this process, giving the rst results

We match the continuum and lattice axial-vector and vector currents at one loop in perturbation theory. For the heavy quarks we use the nonrelativistic QCD (NRQCD) action and for the light quarks the highly improved staggered quark (HISQ) action. We present results for both massless and massive HISQ quarks and as part of the matching procedure we include a discussion of the one loop HISQ renormalization parameters.

We present a lattice investigation, partially including the effects of dynamical quarks, of the heavy-light mesons using NRQCD for the heavy quark and the Wilson action for the light quark. We performed an extensive calculation of the spectrum employing a multi-state, multi-exponential fitting analysis which enabled us to extract the $2S{-}1S$ splitting as well as the $^1P_1{-}\bar{S}$ and hyperfine splittings. The Wilson action introduces a large systematic error into the calculation, and within this uncertainty we obtain agreement with experiment. We performed a comprehensive calculation of the heavy-light meson mass, investigating three methods and their range of validity. The agreement found between these methods confirms that Lorentz invariance can be restored at this order in NRQCD by a constant shift to all masses. We calculated spectroscopic quantities over a wide range in heavy quark mass and were able to perform a detailed investigation of heavy quark symmetry around the $b$ quark mass. In particular, we extracted the nonperturbative coefficients of terms in the heavy quark expansion of the meson binding energy. We demonstrate the importance of using tadpole-improved operators in such a calculation., 34 pages, latex, 40 postscript figures

We present first results for $B_c$ spectroscopy using Lattice Non-Relativistic QCD (NRQCD). For the NRQCD action the leading order spin-dependent and next to leading order spin-independent interactions have been included with tadpole-improved coefficients. We use multi-exponential fits to multiple correlation functions to extract ground and excited $S$ states and give accurate values for the $S$ state hyperfine splitting and the P state ($B^{**}_c$) fine structure, including the effects of $^1P_1/^3P_1$ mixing., 12 pages uuencoded latex file + 1 postscript figure

We present a lattice investigation of heavy-light mesons in the quenched approximation, using non-relativistic QCD for the heavy quark and a clover improved Wilson formulation for the light quark. A comprehensive calculation of the heavy-light spectrum has been performed for various heavy quark masses around the $b$. Our results for the $B_s-B_d$ splitting agree well with the experimental value. We find the $\Lambda_b-B$ splitting to be compatible with experiment, albeit with large error bars. Our $B^*-B$ splitting is slightly low, which could be explained as an effect of quenching. For the first time, we are able to estimate the mass of $P$ states at the $B$ and compare them with experiment., Comment: 24 pages, latex, 10 figures in uuencoded compressed postscript

We combine a light AsqTad antiquark with a nonrelativistic heavy quark to compute the decay constants of heavy-light pseudoscalar mesons using the ensemble of 3-flavor gauge field configurations generated by the MILC collaboration. Preliminary results for $f_{B_s}$ and $f_{D_s}$ are given and status of the chiral extrapolation to $f_B$ is reported. We also touch upon results of the perturbative calculation which matches matrix elements in the effective theory to the full theory at 1-loop order., Comment: Talk delivered at Lattice2003(heavy), 3 pages

Recently we studied the B, Bs, D and Ds meson decay constants using various treatments for the heavy quark. For B mesons, we determined fB, fBs , and fBs / fB with NRQCD bottom quarks. We then combined the ratio fBs / fB and another very precise determination from HPQCD for fBs using heavy HISQ quarks, and extracted fB with 2% total errors. We also calculated fD, fDs , and fDs / fD using HISQ charm quarks. Here we review our results and briefl y discuss their implications for the determination of the CKM matrix elements|Vcd| and |Vcs|.

We discuss preliminaries of a calculation of the form factors for the semileptonic decays B!p‘n, Bs! K‘n, and B! K‘ + ‘ . We simulate with NRQCD heavy and HISQ light valence quarks on the MILC 2+ 1 dynamical asqtad configurations. The form factors are calculated over a range of momentum transfer to allow determination of their shape and the extraction ofjVubj. Additionally, we are calculating ratios of these form factors to those for the unphysical decay Bs! hs. We are studying the possibility of combining these precisely determined ratios with future calculations of Bs! hs using HISQ b-quarks to generate form factors with significantly reduced errors.

We present a new determination of the QCD strong coupling constant based on precise lattice calculations of the $\Upsilon$ spectrum. The largest systematic uncertainty in previous such determinations resulted from the absence of vacuum polarization from light quarks. We substantially reduce this error by including two flavors of dynamical light quarks and extrapolating to three. We find $\alphathree_\V(8.2~\GeV) = 0.196(3)$ for three light flavors, corresponding to $\alphafive_\msbar(M_Z) = 0.115(2)$. This is significantly more accurate than previous determinations using this or any other technique.

We present an update of the D meson decay constant fD using the highly improved staggered quark action for valence charm and light quarks on MILC Nf=2+1 lattices. The new determination incorporates HPQCD’s improved scale r1Nf=2+1=0.3133(23) fm, accurately retuned bare charm quark masses and data from an ensemble that is more chiral than in our previous calculations. We find fD=208.3(3.4) MeV. Combining the new fD with D→μνμ branching fraction data from CLEO-c, we extract the Cabibbo-Kobayashi-Maskawa matrix element |Vcd|=0.223(10)exp(4)lat. This value is in excellent agreement with |Vcd| from D semileptonic decays and from neutrino scattering experiments and has comparable total errors. We determine the ratio between semileptonic form factor and decay constant and find [f+D→π(0)/fD]lat=3.20(15) GeV-1 to be compared with the experimental value of [f+D→π(0)/fD]exp=3.19(18) GeV-1. Finally, we mention recent preliminary but already more accurate D→μνμ branching fraction measurements from BES III and discuss their impact on precision |Vcd| determinations in the future.

We present a new determination of the B and Bs meson decay constants using nonrelativistic quantum chromodynamics (NRQCD) b-quarks, highly improved staggered quark (HISQ) light and strange valence quarks and the MILC collaboration Nf=2+1 lattices. The new calculations improve on HPQCD’s earlier work with NRQCD b-quarks by replacing AsqTad with HISQ valence quarks, by including a more chiral MILC fine ensemble in the analysis, and by employing better tuned quark masses and overall scale. We find fB=0.191(9) GeV, fBs=0.228(10) GeV and fBs/fB=1.188(18). Combining the new value for fBs/fB with a recent very precise determination of the Bs meson decay constant based on HISQ b-quarks, fBs=0.225(4) GeV, leads to fB=0.189(4) GeV. With errors of just 2.1% this represents the most precise fB available today.

We illustrate a technique for fitting lattice QCD correlators to sums of exponentials that is significantly faster than traditional fitting methods --- 10--40 times faster for the realistic examples we present. Our examples are drawn from a recent analysis of the Upsilon spectrum, and another recent analysis of the D -> pi semileptonic form factor. For single correlators, we show how to simplify traditional effective-mass analyses., 5 pages, 4 figures

The spectrum of the \ensuremath{\Upsilon} system is investigated using the nonrelativistic lattice QCD approach to heavy quarks and ignoring light quark vacuum polarization. We find good agreement with experiment for the \ensuremath{\Upsilon},\ensuremath{\Upsilon}',\ensuremath{\Upsilon}'' and for the center of mass and fine structure of the ${\mathrm{\ensuremath{\chi}}}_{\mathit{b}}$ states. The lattice calculations predict bb\ifmmode\bar\else\textasciimacron\fi{} D states with a center of mass at (10.20\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.03) GeV. Fitting procedures aimed at extracting both ground and excited state energies are developed. We calculate a nonperturbative dispersion mass for the \ensuremath{\Upsilon}(1S) and compare it with tadpole-improved lattice perturbation theory.

Recent results from lattice QCD simulations provide a realistic picture, based upon first principles, of [Upsilon] physics. We combine these results with the experimentally measured mass of the [Upsilon] meson to obtain an accurate and reliable value for the [ital b] quark's pole mass. We use two different methods, each of which yields a mass consistent with [ital M][sub [ital b]]=5.0(2) GeV. This corresponds to a bare mass of [ital M][sub [ital b]][sup 0]=4.0(1) GeV in our lattice theory and an [bar M][bar S] mass of [ital M][sub [ital b]][sup [bar M][bar S]]([ital M][sub [ital b]])=4.0(1) GeV. ([bar M][bar S] denotes the modified minimal-subtraction scheme). We discuss the implications of this result for the [ital c]-quark mass.

We present a new calculation of the D→π, lν semileptonic form factor f+D→π(q2) at q2=0 based on “highly improved staggered quark” charm and light valence quarks on MILC Nf=2+1 lattices. Using methods developed recently for HPQCD’s study of D→K, lν decays, we find f+D→π(0)=0.666(29). This signifies a better than factor 2 improvement in errors for this quantity compared to previous calculations. Combining the new result with CLEO-c branching fraction data, we extract the Cabibbo-Kobayashi-Maskawa matrix element |Vcd|=0.225(6)exp(10)lat, where the first error comes from experiment and the second from theory. With a total error of ∼5.3% the accuracy of the direct determination of |Vcd| from D semileptonic decays has become comparable to (and in good agreement with) that from neutrino scattering. We also check for second row unitarity using this new |Vcd|, HPQCD’s earlier |Vcs|, and |Vcb| from the Fermilab Lattice and MILC collaborations. We find |Vcd|2+|Vcs|2+|Vcb|2=0.976(50), improving on the current PDG2010 value.

We give the first accurate results for $B$ and ${B}_{s}$ meson masses from lattice QCD including the effect of $u$, $d$, and $s$ sea quarks, and we improve an earlier value for the ${B}_{c}$ meson mass. By using the highly improved staggered quark (HISQ) action for $u/d$, $s$, and $c$ quarks and NRQCD for the $b$ quarks, we are able to achieve an accuracy in the masses of around 10 MeV. Our results are: ${m}_{B}=5.291(18)\text{ }\text{ }\mathrm{GeV}$, ${m}_{{B}_{s}}=5.363(11)\text{ }\text{ }\mathrm{GeV}$, and ${m}_{{B}_{c}}=6.280(10)\text{ }\text{ }\mathrm{GeV}$. Note that all QCD parameters here are tuned from other calculations, so these are parameter free-tests of QCD against experiment. We also give scalar, ${B}_{s0}^{*}$ and axial-vector, ${B}_{s1}$ meson masses. We find these to be slightly below threshold for decay to $BK$ and ${B}^{*}K$, respectively.

We present a new study of $D$ semileptonic decays on the lattice which employs the highly improved staggered quark action for both the charm and the light valence quarks. We work with MILC unquenched ${N}_{f}=2+1$ lattices and determine the scalar form factor ${f}_{0}({q}^{2})$ for $D\ensuremath{\rightarrow}K$, $l\ensuremath{\nu}$ semileptonic decays. The form factor is obtained from a scalar current matrix element that does not require any operator matching. We develop a new approach to carrying out chiral/continuum extrapolations of ${f}_{0}({q}^{2})$. The method uses the kinematic ``$z$''variable instead of ${q}^{2}$ or the kaon energy ${E}_{K}$ and is applicable over the entire physical ${q}^{2}$ range. We find ${f}_{0}^{D\ensuremath{\rightarrow}K}(0)\ensuremath{\equiv}{f}_{+}^{D\ensuremath{\rightarrow}K}(0)=0.747(19)$ in the chiral plus continuum limit and hereby improve the theory error on this quantity by a factor of $\ensuremath{\sim}4$ compared to previous lattice determinations. Combining the new theory result with recent experimental measurements of the product ${f}_{+}^{D\ensuremath{\rightarrow}K}(0)*|{V}_{cs}|$ from BABAR and CLEO-c leads to a very precise direct determination of the CKM matrix element $|{V}_{cs}|$, $|{V}_{cs}|=0.961(11)(24)$, where the first error comes from experiment and the second is the lattice QCD theory error. We calculate the ratio ${f}_{+}^{D\ensuremath{\rightarrow}K}(0)/{f}_{{D}_{s}}$ and find $2.986\ifmmode\pm\else\textpm\fi{}0.087\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ and show that this agrees with experiment.

By using the Highly Improved Staggered Quark formalism to handle charm, strange and light valence quarks in full lattice QCD, and NRQCD to handle bottom valence quarks we are able to determine accurately ratios of the B meson vector-pseudoscalar mass splittings, in particular, (m(B*_c)-m(B_c))/(m(B*_s)-m(B_s)). We find this ratio to be 1.15(15), showing the `light' quark mass dependence of this splitting to be very small. Hence we predict m(B_c*) = 6.330(7)(2)(6) GeV where the first two errors are from the lattice calculation and the third from existing experiment. This is the most accurate prediction of a gold-plated hadron mass from lattice QCD to date., Comment: 4 pages, 2 figures

A U(1)×U(1) Yukawa model with staggered fermions is investigated in the broken phase. Spontaneous symmetry breaking on finite lattices is studied in two ways. In the first approach, which is similar to what is done in lattice QCD studies, we work with nonzero bare-fermion masses and try to extrapolate to the massless limit. In the second method, which to date has been the more common approach in Higgs-Yukawa models, we simulate directly the zero-bare-fermion-mass theory and carry out a global rotation on the fields before taking measurements. In the m f ≠0 calculations Ward identities are monitored to asses the quality of the simulations and both fermion-antifermion and purely bosonic operators are used in Goldstone boson correlation-functions. We point out differences between the fermion-antifermion channel in the current model and analogous calculations of the pion correlation-function in lattice QCD. We show that noisy estimates of the fundamental fermion propagator can also be used very effectively for meson correlations, where the fermion and antifermion annihilate into pure bosonic matter (the so called annihilation channel). Estimates for renormalized Yukawa and λφ 4 couplings obtained via the two methods, m f = 0 and m f ≠ 0, are also presented. Renormalized Yukawa-couplings are never much larger than the value obtained from the tree-level j = 0 partial wave unitarity bound for fermion-antifermion elastic scattering in a continuum theory with the appropriate number of flavors.

We give improved results for B meson masses using NRQCD $b$ quarks and HISQ light valence quarks for a range of lattice spacings and sea quark masses enabling controlled extrapolation to the physical point.

We study $B_d$ and $B_s$ mixing in unquenched lattice QCD employing the MILC collaboration gauge configurations that include u, d, and s sea quarks based on the improved staggered quark (AsqTad) action and a highly improved gluon action. We implement the valence light quarks also with the AsqTad action and use the nonrelativistic NRQCD action for the valence b quark. We calculate hadronic matrix elements necessary for extracting CKM matrix elements from experimental measurements of mass differences $\Delta M_d$ and $\Delta M_s$. We find $\xi = f_{B_s} \sqrt{\hat{B}_{B_s}} / f_{B_d} \sqrt{\hat{B}_{B_d}} = 1.258(33)$, $f_{B_d} \sqrt{\hat{B}_{B_d}} = 216(15)$ MeV and $f_{B_s} \sqrt{\hat{B}_{B_s}} = 266(18)$ MeV. We also update previous results for decay constants and obtain $f_{B_d} = 190(13)$ MeV, $f_{B_s} = 231(15)$ MeV and $f_{B_s}/f_{B_d} = 1.226(26)$. The new lattice results lead to updated values for the ratio of CKM matrix elements $|V_{td}|/|V_{ts}|$ and for the Standard Model prediction for $Br(B_s \rightarrow \mu^+ \mu^-)$ with reduced errors. We determine $|V_{td}|/|V_{ts}| = 0.214(1)(5)$ and $Br(B_s \rightarrow \mu^+ \mu^-) = 3.19(19) \times 10^{-9}$., Comment: 12 pages, 10 postscript figures, version to appear in Phys.Rev.D. Two new figures, Fig.6 and Fig.10, added. Result on branching fraction Br(B_s \rightarrow mu^+, mu^-) added. Other results on decay constants and on \xi unchanged

By using a single formalism to handle charm, strange and light valence quarks in full lattice QCD for the first time, we are able to determine ratios of quark masses to 1%. For $m_c/m_s$ we obtain 11.85(16), an order of magnitude more precise than the current PDG average. Combined with 1% determinations of the charm quark mass now possible this gives $\bar{m}_s(2{\rm GeV}) =$ 92.4(1.5) MeV. The MILC result for $m_s/m_l = 27.2(3) $ yields $\bar{m}_l(2{\rm GeV})$ = 3.40(7) MeV for the average of $u$ and $d$ quark masses., Comment: 4 pages, 2 figures. Version accepted by Physical Review Letters. Changes include modifying the title, using the MILC value for m_s/m_l which changes slightly the resulting up and down quark masses and their average, adding some references and making other small adjustments to the text for space reasons.

We present further results for one-loop matching of heavy-light axial and vector currents between continuum QCD and a lattice theory with NRQCD heavy quarks and massless clover quarks., LATTICE98(heavyqk)