We present results of a large-scale simulation for the Kaon B parameter BK in quenched lattice QCD with the Kogut-Susskind quark action. Calculating BK at 1% statistical accuracy for seven values of lattice spacing in the range a ≈ 0.24 − 0.04 fm on lattices up to 563 × 96, we verify a quadratic a dependence of BK theoretically predicted. Strong indications are found that, with our level of acc...

We demonstrate that lattice QCD calculations can be made 103– 10 times faster by using very coarse lattices. To obtain accurate results, we replace the standard lattice actions by perturbativelyimproved actions with tadpole-improved correction terms that remove the leading errors due to the lattice. To illustrate the power of this approach, we calculate the static-quark potential, and the charm...

This paper characterizes those finite lattices which are a maximal sublattice of an infinite lattice. There are 145 minimal lattices with this property, and a finite lattice has an infinite minimal extension if and only if it contains one of these 145 as a sublattice. In [12], I. Rival showed that if L is a maximal sublattice of a distributive lattice K with |K| > 2, then |K| ≤ (3/2)|L|. In [1]...

Lattice QCD with Wilson fermions generically shows the phenomenon of a first order phase transition. We study the phase structure of lattice QCD using Wilson twisted mass fermions and the Wilson plaquette gauge action are used in a range of β values where such a first order phase transition is observed. In particular, we investigate the dependence of the first order phase transition on the valu...

We study random triangulations of the integer points [0, n] ∩ Z, where each triangulation σ has probability measure λ|σ| with |σ| denoting the sum of the length of the edges in σ. Such triangulations are called lattice triangulations. We construct a height function on lattice triangulations and prove that, in the whole subcritical regime λ < 1, the function behaves as a Lyapunov function with r...

The strong coupling constant αs(μ0), taken at a fixed reference scale μ0, is the single free parameter of QCD and should be known to the highest available precision. The value of αs should also be determined with good accuracy over as large a range of scales as possible, in order to reveal potential anomalous running in the strength of the strong interaction. Lattice QCD is now able to calculat...

We investigate the continuum limit of the low lying static-light meson spectrum using Wilson twisted mass lattice QCD with Nf = 2 dynamical quark flavours. We consider three values of the lattice spacing a ≈ 0.051 fm , 0.064 fm , 0.080 fm and various values of the pion mass in the range 280MeV ∼mPS ∼ 640MeV. We present results in the continuum limit for light cloud angular momentum j = 1/2 , 3/...

A lattice QCD calculation of the B̄→Dl n̄ decay form factors is presented. We obtain the value of the form factor h1(w) at the zero-recoil limit w51 with high precision by considering a ratio of correlation functions in which the bulk of the uncertainties cancels. The other form factor h2(w) is calculated, for small recoil momenta, from a similar ratio. In both cases, the heavy quark mass depende...

We determine the radial excitation energy (2S-1S splitting)in the Upsilon spectrum using NRQCD b quarks on MILC configurations. We have statistical fitting errors of around 1% across a range of lattice spacing values using random wall sources, and this allows us to give improved determinations of the physical value of the heavy quark potential parameter r1. We also show improved results for the...

In this talk I review some aspects of the idea that there is an infra-red conformal fixedpoint at the TeV scale. In particular, it is shown how gauge coupling unification can be achieved by TeV unification in a semi-simple gauge group.