Related papers: Electromagnetic effects in eta --> 3 pi
The effective Lagrangian for \eta' incorporating the effect of the QCD \theta-angle has been developed previously. We revisit this Lagrangian and carry out its canonical quantization with particular attention to the test function spaces of…
We find third-power nonlinear corrections to the Coulomb and other static electric fields, as well as to the electric and magnetic dipole fields, as we work within QED with no background field. The nonlinear response function we base our…
Measurement of the $\gamma 3\pi$ process has revealed a possible conflict with what should be a solid prediction generated by the chiral anomaly. We show that inclusion of appropirate energy-momentum dependence in the matrix element reduces…
We present results for the QED contributions to the anomalous magnetic moment of the muon containing closed electron loops. The main focus is on perturbative corrections at four-loop order where the external photon couples to the external…
I discuss isospin breaking effects within the standard model. Chiral perturbation theory presents the appropriate theoretical framework for such an investigation in the low--energy range. Recent results on the electromagnetic contributions…
The electromagnetic contribution to the isomultiplet mass splittings of heavy mesons is reanalyzed within the framework of the heavy mass expansion. It is shown that the leading term in the expansion is given to a good approximation by the…
In this talk we present some preliminary results and discuss the prospects of determining the leading structure-dependent finite-volume effects in the hadronic vacuum polarisation associated to order $e^2$ electromagnetic corrections. In…
The decay K_L -> pi0 gamma e+ e- occurs at a it higher rate than the nonradiative process K_L -> pi0 e+ e-, and hence can be a background to CP violation studies using the latter reaction. It also has an interest in its own right in the…
We calculate the ${\cal O}(\alpha_{{\rm ew}})$ electroweak radiative corrections to $e^+ e^- \to t \bar{t} h$ at a electron-positron linear collider (LC) in the standard model. We analyze the dependence of the ${\cal O}(\alpha_{{\rm ew}})$…
The five different CP conserving amplitudes for the decays $K\to3\pi$ are calculated using Chiral Perturbation Theory. The calculation is made to next-to-leading order and includes full isospin breaking. The squared amplitudes are compared…
The around-the-mean-field version of the LDA+U method is applied to investigate electron correlation effects in $\delta$-Pu. It yields a non-magnetic ground state of $\delta-$Pu, and provides a good agreement with experimental equilibrium…
We consider a scenario (supported by some lattice results) in which a U(1)-breaking condensate survives across the chiral transition in QCD. This scenario has important consequences for the pseudoscalar-meson sector, which can be studied…
We study magnetic dipole (M1) transitions between two quarkonia in the framework of non-relativistic effective field theories of QCD. Relativistic corrections of relative order v^2 are investigated in a systematic fashion. Non-perturbative…
In this thesis we discuss the decays of the pseudoscalar mesons (the neutral pion, the eta and eta-prime) which are governed by the chiral anomaly. Some of these decays are of special interest because their study permits a deep insight into…
Recently, it was shown that in inclusive B -> Xs l+ l- decay, an angular decomposition provides three independent (q^2 dependent) observables. A strategy was formulated to extract all measurable Wilson coefficients in B -> Xs l+ l- from a…
We calculate the leading-logarithmic and next-to-leading-logarithmic electroweak corrections to the charm-top-quark contribution to the effective $|\Delta S| = 2$ Lagrangian, relevant for the parameter $\epsilon_K$. We find that these…
We employ Heavy Baryon Chiral Perturbation Theory (HB$\chi$PT), a non-relativistic effective field theory that treats baryons as heavy static sources, to calculate the electromagnetic polarizabilities of spin-3/2 baryons in two sectors: the…
We consider the flavour sextet of charmed meson resonances with J^P= 1^+ quantum numbers that is predicted by the leading order chiral Lagrangian with up, down and strange quarks. The effect of chiral correction terms as determined…
We construct a low-energy effective field theory that permits the complete treatment of isospin-breaking effects in nonleptonic weak interactions to next-to-leading order. To this end, we enlarge the chiral Lagrangian describing strong and…
We discuss one-loop electroweak corrections to the decay width of toponium. We calculate the energy-level shifts by expanding around the solution of the Bethe-Salpeter equation in the instantaneous approximation, in analogy with the…