Related papers: Analytic estimates for penguin operators in quench…
We show that it is possible to construct $\epsilon^\prime/\epsilon$ to NLO using partially quenched chiral perturbation theory (PQChPT) from amplitudes that are computable on the lattice. We demonstrate that none of the needed amplitudes…
We investigate two-point correlation functions of left-handed currents computed in quenched lattice QCD with the Neuberger-Dirac operator. We consider two lattice spacings a~0.09,0.12 fm and two different lattice extents L~ 1.5, 2.0 fm;…
I describe recent developments in quenched chiral perturbation theory (QChPT) and the status of weak matrix elements involving light quarks. I illustrate how, with improved statistical errors, and with calculations of the masses of baryons…
The dependence of the pseudoscalar meson mass and decay constant is compared to one-loop Partially Quenched Chiral Perturbation Theory (PQChPT) in a numerical simulation with two light dynamical quarks. The characteristic behaviour with…
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…
The SM prediction for the ratio $\varepsilon^\prime/\varepsilon$ appears to be significantly below the experimental data. Also $\varepsilon_K$ in the SM tends to be below the data. Any NP removing these anomalies will first of all have…
Measurements of the lowest-lying eigenvalues of the staggered fermion Dirac operator are made on ensembles of equilibrium gauge field configurations in quenched SU(3) lattice gauge theory. The results are compared with exact analytical…
Two twisted doublets, one containing the up and down quarks and the other containing the strange quark with an SU(2)-flavor partner, are used for studies in the meson sector. The relevant chiral perturbation theory is presented, and…
We present results for the \Delta S=2 matrix elements which are required to study neutral kaon mixing in the standard model (SM) and beyond (BSM). We also provide leading chiral order results for the matrix elements of the electroweak…
In the absence of the QCD penguin contributions a measurement of the time-dependent asymmetry in the decay $B^0(t)\to \pi^+\pi^-$ gives directly the weak angle $\alpha$. Several bounds have been proposed in the literature on the magnitude…
We investigate the use of two kinds of staggered fermion operators, smeared and unsmeared. The smeared operators extend over a $4^4$ hypercube, and tend to have smaller perturbative corrections than the corresponding unsmeared operators. We…
The spectral properties of the Wilson-Dirac operator in 2-dimensional QED responsible for the appearance of exceptional configurations in quenched simulations are studied in detail. The mass singularity structure of the quenched functional…
Quenched chiral perturbation is used to study the decay constants for heavy-light mesons beyond the leading order in 1/M. The results are used to estimate the error in quenched lattice calculations of the decay constants. For the double…
We discuss the renormalization of local, scalar and pseudoscalar dimension-5 operators containing a heavy and a light quark field at scales below the heavy-quark mass, using the formalism of the heavy-quark effective theory (HQET). We…
This paper summarizes the recent calculations of the masses and decay constants of the pseudoscalar mesons at the two-loop level, or NNLO, in Partially Quenched Chiral Perturbation Theory (PQxPT). Possible applications include chiral…
We study quenched QCD at finite chemical potential, $\mu_I$, for the third component of isospin and quenched two-colour QCD at finite chemical potential, $\mu$, for quark number. In contrast to the quenched approximation to QCD at finite…
We report on our ongoing effort to understand quenched lattice QCD at finite baryon number density. The quenched theory is sensitive to the baryon mass both at strong coupling and in the scaling region. However, we find that the quenched…
Motivated by the recent experimental data, we have revisited the $B\to \pi K,\pi \pi$ decays in the framework of QCD factorization, with inclusion of the important strong penguin corrections of order $\alpha_s^2$ induced by $b\to D g^\ast…
We apply different types of overlap operators in quenched QCD simulations to compute the zero mode contribution to the pseudo-scalar correlator. In particular we use the conventional Neuberger Dirac operator and the overlap hypercube Dirac…
We point out that a sizable strong phase could be generated from the penguin annihilation in the soft-collinear effective theory for B meson decays. Keeping a small scale suppressed by O(Lambda/m_b), Lambda being a hadronic scale and m_b…