E. T. Neil

Lattice study of the conformal window in QCD-like theories

We study the extent of the conformal window for an SU(3) gauge theory with N{f} Dirac fermions in the fundamental representation. We present lattice evidence for 12<or=N{f}<or=16 that the infrared behavior is governed by a fixed point, while confinement and chiral symmetry breaking are present for N{f}<or=8.

B- and D-meson decay constants from three-flavor lattice QCD

We calculate the leptonic decay constants ofB (s) andD (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 congurations which include the eects of three light dynamical sea quarks. We simulate with several values of the light valence- and sea-quark masses (down to ms=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, fBs = 242:0(9:5) MeV, f D+ = 218:9(11:3) MeV, fDs = 260:1(10:8) MeV, and the SU(3) avor-breaking ratios fBs =fB = 1:229(26) and fDs =fD = 1:188(25), where the numbers in parentheses are the total statistical and systematic uncertainties added in quadrature.

Lattice study of conformal behavior in SU(3) Yang-Mills theories

Using lattice simulations, we study the extent of the conformal window for an SU(3) gauge theory with N{sub f} Dirac fermions in the fundamental representation. We extend our recently reported work, describing the general framework and the lattice simulations in more detail. We find that the theory is conformal in the infrared for N{sub f}=12, governed by an infrared fixed point, whereas the N{sub f}=8 theory exhibits confinement and chiral symmetry breaking. We therefore conclude that the low end of the conformal window N{sub f}{sup c} lies in the range 8{<=}N{sub f}{sup c}{<=}12. We discuss open questions and the potential relevance of the present work to physics beyond the standard model.

B(s)0-mixing matrix elements from lattice QCD for the Standard Model and beyond

We calculate---for the first time in three-flavor lattice QCD---the hadronic matrix elements of all five local operators that contribute to neutral

Refining new-physics searches in B→Dτν with lattice QCD.

{B}^{0}

Lattice Simulations and Infrared Conformality

- and

B→Kl+l−decay form factors from three-flavor lattice QCD

{B}_{s}

Refining New-Physics Searches inB→Dτνwith Lattice QCD

-meson mixing in and beyond the Standard Model. We present a complete error budget for each matrix element and also provide the full set of correlations among the matrix elements. We also present the corresponding bag parameters and their correlations, as well as specific combinations of the mixing matrix elements that enter the expression for the neutral

Strongly interacting dynamics and the search for new physics at the LHC

B

Erratum: B s→D s/B→D semileptonic form-factor ratios and their application to BR(Bs0→μ +μ -)

-meson width difference. We obtain the most precise determination to date of the SU(3)-breaking ratio