236 citations · 1.5k across the 57 of their papers we have counts for
27 papers · 1 filter
Improving the Kinetic Couplings in Lattice Non-Relativistic QCD
Christine T. H. Davies, Judd Harrison, Ciaran Hughes +3
We improve the non-relativistic QCD (NRQCD) action by comparing the dispersion relation to that of the continuum through in perturbation theory. The one-loop mat…
Rare decays using lattice QCD form factors
R. R. Horgan, Z. Liu, S. Meinel +1
In this write-up we review and update our recent lattice QCD calculation of , , and form factors [arXiv:1310.3722]. These unquenched calculation…
B-meson mixing from full lattice QCD with physical u, d, s and c quarks
R. J. Dowdall, C. T. H. Davies, R. R. Horgan +3
We present the first lattice QCD calculation of the and mixing parameters with physical light quark masses. We use MILC gluon field configurations that include , …
Matching lattice and continuum four-fermion operators with nonrelativistic QCD and highly improved staggered quarks
Christopher Monahan, Elvira Gamiz, Ron Horgan +1
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 qua…
Lattice QCD calculation of form factors describing the rare decays and
Ronald R. Horgan, Zhaofeng Liu, Stefan Meinel +1
The rare decays and are now being observed with enough precision to test Standard Model predictions. A full understanding of these decay…
B, Bs, K and pi weak matrix elements with physical light quarks
R. J. Dowdall, C. T. H. Davies, R. R. Horgan +4
Calculations of pseudoscalar decay constants of B, Bs, K and pi mesons with physical light quarks are presented. We use HISQ ensembles that include u,d,s and c sea quarks at three…
The mass of the b-quark from lattice NRQCD and lattice perturbation theory
A. J. Lee, C. J. Monahan, R. R. Horgan +3
We present a determination of the b-quark mass accurate through O(α_s^2) in perturbation theory and including partial contributions at O(α_s^3). Nonperturbative input comes from th…
Radiative improvement of spin and Darwin terms in the NRQCD action
T. C. Hammant, A. G. Hart, G. M. von Hippel +2
We present updated results for the radiative improvement of the σ.B term and the spin-dependent four-fermion terms in the lattice NRQCD action, and first results for the radiative…
Precise Determinations of the Decay Constants of B and D mesons
Heechang Na, Chris Monahan, Christine Davies +4
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…
Matching heavy-light currents with NRQCD and HISQ quarks
Christopher Monahan, Christine Davies, Ron Horgan +3
We calculate the one loop renormalisation parameters for the heavy-light axial-vector and vector currents using lattice perturbation theory. We use NonRelativistic QCD (NRQCD) heav…
Matching lattice and continuum axial-vector and vector currents with NRQCD and HISQ quarks
Christopher Monahan, Junko Shigemitsu, Ron Horgan
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 t…
The Upsilon spectrum and the determination of the lattice spacing from lattice QCD including charm quarks in the sea
R. J. Dowdall, B. Colquhoun, J. O. Daldrop +8
We give results for the Upsilon spectrum from lattice QCD using an improved version of the NRQCD action for b quarks which includes radiative corrections to kinetic terms at O(v^4)…
Form factors for rare B decays: strategy, methodology, and numerical study
Zhaofeng Liu, Stefan Meinel, Alistair Hart +3
We investigate the combined use of moving NRQCD and stochastic sources in lattice calculations of form factors describing rare B and B_s decays. Moving NRQCD leads to a reduction o…
Moving NRQCD for heavy-to-light form factors on the lattice
R. R. Horgan, L. Khomskii, S. Meinel +9
We formulate Non-Relativistic Quantum Chromodynamics (NRQCD) on a lattice which is boosted relative to the usual discretization frame. Moving NRQCD (mNRQCD) allows us to treat the…
Precision charm physics, m_c and alpha_s from lattice QCD
C. T. H. Davies, E. Gregory, I. Kendall +10
We present an update of results from the HPQCD collaboration on charm physics using the Highly Improved Staggered Quark action. This includes a precise determination of m_c using m…
Rare B decays with moving NRQCD and improved staggered quarks
Stefan Meinel, Eike H. Müller, Lew Khomskii +3
We calculate form factors relevant for rare B decays using moving-NRQCD for the b quark and the AsqTad action for the light quarks. Moving NRQCD allows us to work directly with the…
High-Precision Charm-Quark Mass and QCD Coupling from Current-Current Correlators in Lattice and Continuum QCD
I. Allison, E. Dalgic, C. T. H. Davies +12
We use lattice QCD simulations, with MILC gluon configurations and HISQ c-quark propagators, to make very precise determinations of moments of charm-quark pseudoscalar, vector and…
Moving NRQCD and B to K* gamma
Stefan Meinel, Ronald Horgan, Lew Khomskii +2
The formulation of NRQCD discretized in a reference frame boosted relative to the B rest frame will enable calculation of B form factors over a larger range of momentum transfer. W…
Leptonic widths of heavy quarkonia: QCD/NRQCD matching for the electromagnetic current at O(α_s v^2)
A. Hart, G. M. von Hippel, R. R. Horgan
We construct the S-wave part of the electromagnetic vector annihilation current to , where is the non-relativistic quark velocity, for heavy quarks whose dynamics a…
Leptonic widths of heavy quarkonia: S-Wave QCD/NRQCD matching coefficients for the electromagnetic vector annihilation current at O(alpha_s v^2)
A. Hart, G. M. von Hippel, R. R. Horgan
We construct the S-wave part of the electromagnetic vector annihilation current to O(alpha_s v^2)$ on the lattice for heavy quarks whose dynamics are described by the NRQCD action,…
High Precision Fundamental Constants using Lattice Perturbation Theory
Quentin Mason, Howard Trottier, Ron Horgan
The HPQCD collaboration has a program for determining the fundamental constants of the Standard Model Lagrangian from lattice QCD. The most accurate method of doing this uses the n…
Automatically generating Feynman rules for improved lattice field theories
A. Hart, G. M. von Hippel, R. R. Horgan +1
Deriving the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially when improvement terms are present. This physically important task…
Perturbation theory vs. simulation for tadpole improvement factors in pure gauge theories
A. Hart, R. R. Horgan, L. C. Storoni
We calculate the mean link in Landau gauge for Wilson and improved SU(3) anisotropic gauge actions, using two loop perturbation theory and Monte Carlo simulation employing an accel…
Gauged O(n) spin models in one dimension
M. Hasenbusch, R. R. Horgan
We consider a gauged O(n) spin model, n >= 2, in one dimension which contains both the pure O(n) and RP(n-1) models and which interpolates between them. We show that this model is…