Related papers: Renormalon Ambiguities in NRQCD Operator Matrix El…
In this paper, we show that the common hard kernel of double-log-type or threshold-type factorization for certain space-like parton correlators that arise in the context of lattice parton distributions, the heavy-light Sudakov hard kernel,…
We present a GUT-model-independent calculation of hadron matrix elements for all dimension-six operators associated with baryon number violating processes using lattice QCD. Our results cover all the matrix elements required to estimate the…
We determine the leading-order nonrelativistic quantum chromodynamics (NRQCD) matrix element < O_1 >_Upsilon and the ratio < q^2>_Upsilon, for Upsilon=Upsilon(nS) with n=1, 2, and 3 by comparing the measured values for Gamma[Upsilon -> e^+…
A short survey of the renormalization problem in QCD and its non-perturbative solution by means of numerical simulations on the lattice is given. Most emphasis is on scale dependent renormalizations, which can be reliably addressed via a…
In QCD sum-rule methods, the fundamental field-theoretical quantities are correlation functions of composite operators that serve as hadronic interpolating fields. One of the challenges of loop corrections to QCD correlation functions in…
A QCD factorization formalism was recently proposed for evaluating heavy quarkonium production at large $p_T$ at collider energies. With systematically calculated short-distance partonic hard parts and evolution kernels of fragmentation…
We present non-perturbative renormalization factors for $\Delta S=2$ four-quark operators in quenched domain-wall QCD using the Schroedinger functional method. Non-perturbative renormalization factor for $B_K$ is evaluated at hadronic…
The `renormalon' or `dispersive' method for estimating non-perturbative corrections to QCD observables is reviewed. The corrections are power-suppressed, i.e. of the form $A/Q^p$ where $Q$ is the hard process momentum scale. The renormalon…
We consider the renormalisation of lattice QCD operators with one and two covariant derivatives related to the first and second moments of generalised parton distributions and meson distribution amplitudes. Employing the clover fermion…
We calculate the form factors for weak decays of $B_{(s)}$ and $D_{(s)}$ mesons to light pseudoscalar and vector mesons. To reveal the intimate connection between different decay modes and to be able to perform the calculations in the full…
We argue that the renormalization factors for nonlocal quark-antiquark and gluon operators at space-like and time-like separations connected by a Wilson line coincide to all orders in perturbation theory. We calculate the anomalous…
High-order behavior of the perturbative expansion for short-distance observables in QCD is intimately related to the contributions of small momenta in the corresponding Feynman diagrams and this correspondence provides one with a useful…
These lectures describe in detail the effective Hamiltonians for weak decays of mesons constructed by means of the operator product expansion and the renormalization group method. We calculate Wilson coeffcients of local operators, discuss…
We derive and solve the renormalisation-group (RG) equation of the shape function $g_{17}(\omega,\omega_1;\mu)$, which appears at subleading power in the factorization of the inclusive decays $\bar{B} \to X_s \gamma$ and $\bar B \to X_s…
Some examples of the most recent applications of the NRQCD factorization approach to quarkonium phenomenology are presented. In the first part of the talk the NLO calculations for $\chicj$ and $\Upsilon$ decays rates are compared to the…
We suggest to use operator product expansion and QCD sum rule techniques to estimate the long-distance contribution to the amplitude of the exclusive rare decay $B\to K^* \gamma$. In contrast to a phenomenological description in terms of…
Motivated by the problem of channel estimation in wireless communications, we derive a reconstruction formula for pseudodifferential operators with a bandlimited symbol. This reconstruction formula uses the diagonal entries of the matrix of…
For precise QCD prediction of observables, the ambiguity due to renormalons in perturbative calculations should be appropriately separated from Wilson coefficients in the framework of the operator-product-expansion. Recently, a new method…
We introduce a new parameterization of four-fermion matrix elements which does not involve quark masses and thus allows a reduction of systematic uncertainties in physical amplitudes. As a result the apparent quadratic dependence of e'/e on…
Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an…