Related papers: Exploring two non-perturbative definitions of $c_A…
Partial quenching allows one to consider correlation functions and amplitudes that do not arise in the corresponding unquenched theory. For example, physical $s$-wave pion scattering can be decomposed into $I=0$ and $2$ amplitudes, while,…
Detailed analysis shows that the phase of a complex mass term of a quark does not violate CP, while the QCD vacuum angle can naturally be set equal to zero. There is no strong CP problem and no need for axions or similar speculative…
The quantum null energy condition (QNEC) is a conjectured bound on components $(T_{kk} = T_{ab} k^a k^b$) of the stress tensor along a null vector $k^a$ at a point $p$ in terms of a second $k$-derivative of the von Neumann entropy $S$ on…
We have determined the non-perturbative O(a)-improvement coefficient c_sw for four flavors of Wilson quarks with the plaquette gauge action in a range of beta >= 5. The data are fitted with several Pade approximation formulae to get an…
We argue from LQCD that there is a non vanishing v.e.v of $A_a^\mu A^a_\mu$ in QCD in the Landau gauge. We use operator product expansion to provide a clear definition of $A_a^\mu A^a_\mu$ and extract a number both in the quenched and…
Quenched and partially quenched chiral perturbation theory for vector mesons is developed and is used to extract chiral loop correction to the $\rho$ meson mass. Connections to fully quenched and totally unquenched chiral perturbation…
The global center symmetry of quenched QCD at zero baryonic chemical potential is broken spontaneously at a critical temperature $T_c$ leading to a first-order phase transition. Including heavy dynamical quarks breaks the center symmetry…
We carry out a perturbative determination of mass dependent renormalization factors and $O(a)$ improvement coefficients for the vector and axial vector currents with a relativistic heavy quark action, which we have designed to control…
A perturbative expansion for QED and QCD bound states is formulated in $A^0=0$ gauge. The constituents of each Fock state are bound by their instantaneous interaction. In QCD an O($\alpha_s^0$) confining potential arises from a homogeneous…
The quenched approximation for QCD is, at present and in the foreseeable future, unavoidable in lattice calculations with realistic choices of the lattice spacing, volume and quark masses. In this talk, I review an analytic study of the…
This series of lectures consists of two parts. In the first part the foundations of perturbative and non perturbative formulation are discussed. The ambiguity in the definition of vacuum condensates is then analyzed. In the second part the…
In this paper we study the central limit theorem and its functional form for random fields which are not started from their equilibrium, but rather under the measure conditioned by the past sigma field. The initial class considered is that…
We calculate the static quark and anti-quark potential both in quenched and two-flavor dynamical quark lattice QCD using DBW2 gauge and domain-wall quark actions. Lattice spacings from Sommer scale are determined. We find (i) mixing of…
We present our latest results for the Delta I=1/2 rule, obtained on quenched ensembles with beta=6.0 and 6.2, and a set of N_f=2 configurations with beta=5.7. The statistical noise is quite under control. We observe an enhancement of the…
The QCD Equation of State with $N_f=3$ massless quark flavours is determined non-perturbatively over a broad range of temperatures, extending from the electroweak scale down to 3 GeV, and smoothly connecting to the low-temperature regime.…
In this paper, we calculate mass and probability fractions of meson-meson components of $X(3872)$ in an unquenched quark model. Different from most of other unquenched quark models, the quark pairs creation operator from $^3P_0$ is modified…
We investigate the dependence of the QCD vacuum structure on the $\theta$-angle and quark mass, using the Di-Vecchia--Veneziano model. Although the Di-Vecchia--Veneziano model is a chiral effective model, it contains the topological…
We present results on the equation of state in QCD with two light quark flavors and a heavier strange quark. Calculations with improved staggered fermions have been performed on lattices with temporal extent Nt =4 and 6 on a line of…
In order to study the running coupling in four-flavour QCD, we review the set-up of the Schr\"odinger functional (SF) with staggered quarks. Staggered quarks require lattices which, in the usual counting, have even spatial lattice extent…
We calculate the partition function of partially quenched chiral perturbation theory in the epsilon regime at next-to-leading order using the supersymmetry method in the formulation without a singlet particle. We include a nonzero imaginary…