Related papers: Additional Isospin-Breaking Effects in epsilon'/ep…
We describe some recent results on isospin breaking corrections which are of relevance for predictions of the leading order hadronic contribution to the muon anomalous magnetic moment (amuhadLO) when using tau lepton data. When these…
Sea-quark isospin-breaking effects (IBE) are difficult to compute since they require the evaluation of all-to-all propagators. However, the quest for high-precision calculations motivates a detailed study of these contributions. There are…
We calculate the contributions of the Kaluza-Klein (KK) modes to the gamma-penguins, gluon-penguins, gamma-magnetic penguins and chromomagnetic penguins in the Appelquist, Cheng and Dobrescu (ACD) model with one universal extra dimension.…
We use chiral perturbation theory to evaluate the scattering amplitude for the process Pi^+ K^- to Pi^+ K^- at leading and next-to-leading orders in the chiral counting and in the presence of isospin breaking effects. We also discuss the…
Recently the RBC-UKQCD lattice collaboration presented new results for the hadronic matrix elements relevant for the ratio $\varepsilon'/\varepsilon$ in the Standard Model (SM). With the present knowledge of the Wilson coefficients and…
We present a new method to evaluate with high precision isospin breaking effects due to the small mass difference between the up and down quarks using lattice QCD. Our proposal is applicable in principle to any hadronic observable which can…
Quenching effects in strong penguin matrix elements are investigated. A lattice determination of $\alpha_q^{NS}$, the constant that appears in the quenched ChPT relevant for the lattice analysis of $K\to\pi\pi$ matrix elements, shows that…
I discuss about a possibility of large electroweak penguin contribution in B --> K pi. To satisfy several relations among the branching ratios, we need large electroweak penguin contribution. The magnitude is larger than the theoretical…
We present a new analysis of the ratio epsilon'/epsilon within the Standard Model (SM) using a formalism that is manifestly independent of the values of leading (V-A)x(V-A) QCD penguin, and EW penguin hadronic matrix elements of the…
The mass splittings in the pseudoscalar mesons are studied by combining 2+1 flavor domain wall fermion gauge configurations, generated by the RBC/UKQCD collaborations, and quenched, non-compact, lattice QED configurations. We extract the…
Lattice QCD simulations are now reaching a precision where isospin breaking effects become important. Previously, we have developed a program to systematically investigate the pattern of flavor symmetry beaking within QCD and successfully…
The effects of isospin violation on the neutral weak magnetic form factor of the proton are studied using two-flavour chiral perturbation theory. The first nonzero contributions appear at O(p^4) in the small-momentum expansion, and the…
We present the results of the effects of various mechanisms on the quark level, including QED-QCD interference effect, on isospin violation in ${}1S_0$ NN scatterings with the new sets of strength parameters obtained by fitting to mass…
It is shown that isospin-breaking corrections to the pion-deuteron scattering length can be very large, because of the vanishing of the isospin-symmetric contribution to this scattering length at leading order in chiral perturbation theory.…
We perform a combined analysis of the unitarity triangle and of the CP violating parameter epsilon'/epsilon using the most recent determination of the relevant experimental data and, whenever possible, hadronic matrix elements from lattice…
We consider penguin contributions to the lifetime splitting between the $B_s$ and the $B_d$ meson. In the Standard Model the penguin effects are found to be opposite in sign, but of similar magnitude as the contributions of the…
We investigate the isospin-violating mixing of the light scalar mesons a0(980) and f0(980) within the unitarized chiral approach. Isospin-violating effects are considered to leading order in the quark mass difference and electromagnetism.…
Using isospin relations, we predict the Standard-Model correlation between S_{pi^0 K_S}=(sin 2beta)_{pi^0 K_S} and A_{pi^0 K_S}, the mixing-induced and direct CP asymmetries of B^0-> pi^0 K_S. The calculation uses flavour SU(3) only to fix…
A consistent census of penguins in the Delta I = 1/2 rule is taken from the eta0 pole contribution to the radiative KL to gamma gamma, KS to pi0 gamma gamma and K+ to pi+ gamma gamma decay modes. We briefly comment on its impact for KL to…
We discuss the theoretical and experimental status of the CP violating ratio eps'/eps. We revise our 1997 standard-model estimate-based on hadronic matrix elements computed in the chiral quark model up to O(p^4) in the chiral expansion-by…