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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (16 download)
Download or read book The $D_s$, $D+̂$, $B_s$ and $B$ Decay Constants from $2+1$ Flavor Lattice QCD. written by and published by . This book was released on 2013 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.:/5 (94 download)
Download or read book B-meson Decay Constants from 2+1-flavor Lattice QCD with Domain-wall Light Quarks and Relativistic Heavy Quarks written by and published by . This book was released on 2015 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall 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[pi] ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O([alpha]sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (727 download)
Download or read book The Decay Constants F(B) and F(D+) from Three-flavor Lattice QCD. written by and published by . This book was released on 2007 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present new preliminary results for the leptonic decay constants f{sub B} and f{sub D+} determined in 2+1 flavor lattice QCD at lattice spacings a = 0.09, 0.12 and 0.15 fm. Results are obtained using the MILC Collaboration gauge configuration ensembles, clover heavy quarks in the Fermilab interpretation and improved staggered light quarks. Decay constants, computed at partially quenched combinations of the valence and sea light quark masses, are used to determine the low-energy parameters of staggered chiral perturbation theory. The physical decay constants are found in an extrapolation using the parameterized chiral formula.
Author : R. T. Evans
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ISBN 13 :
Total Pages : 6 pages
Book Rating : 4.:/5 (316 download)
Download or read book The Decay Constants F(B+) and F(D+) from Three-flavor Lattice QCD. written by R. T. Evans and published by . This book was released on 2006 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present new results for f{sub B+} and f{sub D+} from the MILC 2+1 flavor a = 0.09fm 'fine' lattice. We use clover heavy quarks in the Fermilab interpretation and improved staggered light quarks. Lattice results from partially quenched QCD fix the parameters of staggered chiral perturbation theory which is used in the extrapolation to the physical decay constants.
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ISBN 13 :
Total Pages : 63 pages
Book Rating : 4.:/5 (16 download)
Download or read book B- and D-meson Decay Constants from Three-flavor Lattice QCD. written by and published by . This book was released on 2012 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 heavy-light meson correlation functions on the MILC asqtad-improved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence- and sea-quark masses (down to m̃_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 heavy-light meson staggered chiral perturbation theory. We renormalize the heavy-light axial current using a mostly nonperturbative method such that only a small correction to unity must be computed in lattice perturbation theory and higher-order terms are expected to be small. We obtain f_{B+̂} = 196.9(8.9) MeV, f_{B_s} = 242.0(9.5) MeV, f_{D+̂} = 218.9(11.3) MeV, f_{D_s} = 260.1(10.8) MeV, and the SU(3) flavor-breaking ratios f_{B_s}/f_{B} = 1.229(26) and f_{D_s}/f_{D} = 1.188(25), where the numbers in parentheses are the total statistical and systematic uncertainties added in quadrature.
Download or read book The Ds and D+ Leptonic Decay Constants from Lattice QCD. written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the leptonic decay constants f{sub D{sub s}} and f{sub D{sup +}} computed on the MILC collaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks with the Fermilab interpretation and improved staggered light quarks. The simultaneous chiral and continuum extrapolation, which determines both decay constants, includes partially-quenched lattice results at lattice spacings a (almost equal to) 0.09, 0.12 and 0.15 fm. We have made several recent improvements in our analysis: (a) we include terms in the fit describing leading order heavy-quark discretization effects, (b) we have adopted a more precise input r1 value consistent with our other D and B meson studies, (c) we have retuned the input bare charm masses based upon the new r1. Our preliminary results are f{sub D{sub s}} = 260 ± 10 MeV and f{sub D{sup +}} = 217 ± 10 MeV.
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ISBN 13 :
Total Pages : 5 pages
Book Rating : 4.:/5 (873 download)
Download or read book The Decay Constants FDs and FD+ Form Lattice QCD. written by and published by . This book was released on 2011 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent calculations of the decay constants in lattice QCD are reviewed and compared to experiment. The decay constants are tabulated in Table 2 and plotted in Figure 2. The most precise f{sub Ds} value is from HPQCD. It is about 2[sigma] higher than their previous result. The change is due to a more precise determination of the lattice spacing and better tuning of the quark masses. They have updated f{sub D+} using the new f{sub Ds} and their older f{sub Ds}/f{sub D+} ratio which is expected to be less sensitive to mistuning of the lattice spacing and masses. The preliminary FNAL/MILC f{sub Ds} value is about 1.4[sigma] higher than the HPQCD result but with a larger error. The f{sub D+} values, however, are in better agreement. FNAL/MILC expect to finalize their results once the charm quark mass tuning is complete. The two flavor ETM f{sub D+} value is about 1.6[sigma] lower than the HPQCD value while f{sub Ds} is in better agreement. It is not clear how much of the difference is from neglecting the strange sea quark, given the errors. Lattice and experiment differ most significantly for f{sub Ds}. Figure 3 shows Kronfeld's (updated) history of f{sub Ds}. The yellow bands depict the evolution of the experimental average while the three-flavor lattice average is shown in grey. The right-hand scale and green lines show the differences in sigmas. The 3.8[sigma] discrepancy around t ≈ 2 provoked the 'f{sub Ds} puzzle'. That discrepancy has now shrunk to 1.6[sigma]. Future lattice and experiment will be decisive.
Download or read book Decay Constants of B and D Mesons from Non-pertubatively Improved Lattice QCD. written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The decay constants of B and D mesons are computed in quenched lattice QCD at two different values of the coupling. The action and operators are? (a) improved with non-perturbative coefficients where available. The results and systematic errors are discussed in detail. Results for vector decay constants, flavour symmetry breaking ratios of decay constants, the pseudoscalar-vector mass splitting and D meson masses are also presented.
Author : S. Aoki
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ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (245 download)
Download or read book B Meson Decay Constant from Quenched Lattice QCD written by S. Aoki and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (727 download)
Download or read book B and D Meson Decay Constants written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an update of our calculations of the decay constants of the D, D{sub s}, B, and B{sub s} mesons in unquenched 2+1 flavor QCD. We use the MILC library of improved staggered gauge ensembles at lattice spacings 0.09, 0.12, and 0.15 fm, clover heavy quarks with the Fermilab normalizations, and improved staggered light valence quarks.
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (873 download)
Download or read book B and D Meson Decay Constants from 2+1 Flavor Improved Staggered Simulations written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We give an update on simulation results for the decay constants f{sub B}; f{sub B{sub s}}, f{sub D} and f{sub D{sub s}}. These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity triangle fit. The results presented here make use of the MILC (2+1)-flavor asqtad ensembles, with heavy quarks incorporated using the clover action with the Fermilab method. Partially quenched, staggered chiral perturbation theory is used to extract the decay constants at the physical point. In addition, we give error projections for a new analysis in progress, based on an extended data set.
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (93 download)
Download or read book Leptonic B- and D-Meson Decay Constants with 2+1 Flavors of Asqtad Fermions written by and published by . This book was released on 2015 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the status of our updated D- and B-meson decay-constant analysis, based on the MILC Nf =2+1 asqtad gauge ensembles. Heavy quarks are incorporated using the Wilson clover action with the Fermilab interpretation. This analysis includes ensembles at five lattice spacings from [alpha] ≈ 0.045 to 0.15 fm, and light sea-quark masses down to 1/20th of the strange-quark mass. Projected error budgets for ratios of decay constants, in particular between bottom- and charm-meson decay constants, are presented.
Author : Philippe Boucaud
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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (135 download)
Download or read book B-meson Mass and Decay Constant from Lattice QCD written by Philippe Boucaud and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of the first computation on large lattices of the B-meson binding energy and decay constant following the method proposed by Eichten. The results obtained at ß = 6 on a 20*102*40 lattice and at ß = 6.2 on a 163*48 lattice show that it is necessary to have a statistical sample which is much larger than in similar computations with light mesons in order to obtain results of comparable precision.
Download or read book $B\to Kl^+l^-$ Decay Form Factors from Three-flavor Lattice QCD. written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 multiple sea-quark masses to help control the chiral extrapolation. The asqtad improved staggered action is used for the light valence and sea quarks, and the clover action with the Fermilab interpretation is used for the heavy b quark. We present results for the form factors f+(q2), f0(q2), and fT(q2), where q2 is the momentum transfer, together with a comprehensive examination of systematic errors. Lattice QCD determines the form factors for a limited range of q2, and we use the model-independent z expansion to cover the whole kinematically allowed range. We present our final form-factor results as coefficients of the z expansion and the correlations between them, where the errors on the coefficients include statistical and all systematic uncertainties. Lastly, we use this complete description of the form factors to test QCD predictions of the form factors at high and low q2.
