Related papers: Epsilon'/Epsilon in the Standard Model: Theoretica…
We study the implications of several recent high-precision measurements of the pion form factor in the region of the rho-omega interference "shoulder" for (i) the extraction of the rho-omega mixing matrix element, Pi_{\rho\omega}(m_rho^2),…
We extend in several respects our earlier work on O(p^2) corrections to matrix elements of the electroweak penguin operator O_{ewp}. First, to facilitate comparison with certain lattice studies we calculate O(p^2) corrections to…
In-medium chiral perturbation theory is used to calculate the density dependence of the quark condensate $<\bar qq>$. The corrections beyond the linear density approximation are obtained by differentiating the interaction contributions to…
The branching ratio of the \eta->3\pi decay is an important source of information on the value of the quark mass ratio 1/R=(m_d-m_u)/(m_s-\hat m). Furthermore, isospin breaking effects in the decays K->3\pi provide information on the pion…
A representation of the two-loop contribution to the pion decay constant in $SU(3)$ chiral perturbation theory is presented. The result is analytic upto the contribution of the three (different) mass sunset integrals, for which an expansion…
First preliminary measurement of the direct CP-violating parameter Ag by the NA48/2 experiment at CERN SPS is presented. Using more than 1.6 billions of charged kaon decays into three charged pions, the charge asymmetry in the…
We study the CP asymmetries in $B^+$, $D^+$, and $K^+$ decays into $\pi^+\pi^0$. These asymmetries are commonly known to vanish in the isospin limit. We clarify what is meant by the term ``isospin limit" in this context. We provide a…
We analyse the radiative decay $\eta \to \pi^+\pi^- \pi^0\gamma$ in the low--energy expansion of the Standard Model. We employ the notion of ``generalized bremsstrahlung'' to take full advantage of the theoretical and experimental…
We explore the possible enhancement of direct CP violating parameter epsilon'/epsilon in the general left-right model based on the SU(2)_L times SU(2)_R times U(1) gauge group. The mixing matrix of right-handed quarks, V_{CKM}^R is…
We calculate the pion-pion elastic scattering phase shifts for pion masses from the chiral limit to values of interest for lattice studies. At low energies, we use the standard Chiral Perturbation Theory expressions to one and two loops. In…
We calculate the two form-factors for the four Kaon to pion transitions via a vector current to order $p^6$ in Chiral Perturbation Theory to first order in isospin breaking via the quark masses. In addition we derive relations between these…
We compute the effects of anomalous gauge-boson couplings at high-energy hadron colliders using next-to-leading order $SU(2) \times SU(2)$ chiral perturbation theory. By comparing the yields from the universal $p^2$ terms with those arising…
We calculate the direct $CP$ violation for the decay process of ${B}^{0}\rightarrow \pi^{0}\pi^{0}$, ${B}^{+}\rightarrow \pi^{0}\pi^{+}$, ${B}^{0}\rightarrow K^{0}\pi^{0}$ and ${B}^{+}\rightarrow K^{+}\pi^{0}$ via isospin symmetry breaking…
We study possible so far unaccounted isospin breaking effects in the relation between the pion form factor as determined in e^+e^- experiments and the corresponding quantity obtained after accounting for known isospin breaking effects by an…
We derive a master formula for chiral $SU(2)\times SU(2)$ breaking, based on the Veltman-Bell equations and the Peierls-Dyson relation. Our approach does not rely on the use of the soft pion limit or an expansion around the chiral limit,…
I shortly review the present status of the theoretical estimates of eps'/eps. I consider a few aspects of the theoretical calculations which may be relevant in understanding the present experimental results. I discuss the role of higher…
An isospin analysis of $B\to \pi\pi$ decays yields $\sin 2\alpha$, where $\alpha$ is the usual CKM angle $\alpha\equiv {\rm arg} [-V_{td} V_{tb}^\ast/(V_{ud}V_{ub}^\ast)]$ without hadronic uncertainty if isospin is a perfect symmetry. Yet…
I discuss recent developments on non-leptonic and radiative kaon decays mainly related to direct CP-violation within the combined ChPT and 1/N_c expansion approaches. In particular, I review the status of K -> pi pi, epsilon_K', direct…
We study $\omega\to\pi^+\pi^-$ decay up to including all orders of the chiral expansion and one-loop level of mesons in formlism of chiral constituent quark model. This G-parity forbidden decay is caused by $m_u\neq m_d$ and electromagnetic…
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…