Related papers: Epsilon'/Epsilon in the Chiral Limit using Large N…
The reaction pi N -> pi pi N is studied at tree level up to next-to-leading order in the framework of manifestly covariant baryon chiral perturbation theory with explicit Delta(1232) degrees of freedom. Using total cross section data to…
Nature might be kinder than previously thought as far as epsilon'/epsilon is concerned. We show that the recently obtained experimental value for epsilon'/epsilon does not require sizeable 1/N and isospin-breaking corrections. We propose to…
We derive a universal formula for the one-loop renormalization of the effective K\"ahler potential that applies to general supersymmetric effective field theories of chiral multiplets, with arbitrary interactions respecting N=1…
We construct the general N=1/2 supersymmetric gauge theory coupled to massive chiral matter, and show that it is renormalisable at one loop.
We perform a chiral extrapolation of lattice data on the scalar K pi form factor and the ratio of the kaon and pion decay constants within Chiral Perturbation Theory to two loops. We determine the value of the scalar form factor at zero…
K to pi pi matrix elements of the electroweak operator Q_(27,1)^Delta I=3/2 are calculated on the RBC/UKQCD 32^3 x 64, L_s=16 lattices, using 2+1 dynamical flavors and domain wall fermions, with an inverse lattice spacing of a^(-1)=2.42(4)…
We calculate the correlation functions for the $\bar K^0 p, \pi^+ \Sigma^0, \pi^0 \Sigma^+, \pi^+ \Lambda$, and $\eta \Sigma^+$ states, which in the chiral unitary approach predict an excited $\Sigma^*(1/2^-)$ state at the $\bar K N$…
We compute the large $N$ effective action of the $O(N+1)/O(N)$ non-linear sigma model including the effect of the pion mass to order $m^2_{\pi}/f_{\pi}^2$. This action is more complex than the one corresponding to the chiral limit not only…
The $\pi\pi$ interaction is studied at one loop order in the framework of Generalized Chiral Perturbation theory
The CP conserving amplitudes for the decays $K\to3\pi$ are calculated in Chiral Perturbation Theory. The calculation is made at the next-to-leading order including strong and local electromagnetic isospin breaking. A comparison is made…
The low-energy $\pi\pi$ amplitude is computed explicitly to two-loop accuracy in the chiral expansion. It depends only on six independent (combinations of) low-energy constants which are not fixed by chiral symmetry. Four of these constants…
Talk given at QCD 97, Montpellier, July 1997. In the first part of the talk, I presented a review of the results for the light quark masses obtained on the basis of chiral perturbation theory. As this material is described elsewhere, the…
We calculate long-distance contributions to the amplitudes A(K^0 --> pi pi, I) induced by the gluon and the electroweak penguin operators Q_6 and Q_8, respectively. We use the 1/N_c expansion within the effective chiral lagrangian for…
We calculate the $O(p^6)$ corrections to the anomalous form factors appearing in $\pi^+$, $K^+ \to e^+ \nu \gamma,\ \mu^+\nu\gamma$ and $K_{l4}$ decays in Chiral Perturbation Theory. The relevant dimension $6$ terms of the lagrangian are…
We study the decays Omega^- -> Cascade+pion using heavy-baryon chiral perturbation theory to quantify the |Delta I|=1/2 rule in these decay modes. The ratio of |Delta I|=3/2 to |Delta I|=1/2 amplitudes is somewhat larger in these decays…
We present a calculation of the low energy constants describing the real and imaginary parts of the $K \to \pi \pi$ decay amplitudes $A_0$ and $A_2$. Leading and next leading order chiral perturbation theory is used and its applicability…
Three years after the completion of the next-to-leading order calculation, the status of the theoretical estimates of $\epsilon'/\epsilon$ is reviewed. In spite of the theoretical progress, the prediction of $\epsilon'/\epsilon$ is still…
I summarize the results of the complete one--loop chiral perturbation theory calculation performed recently. It is shown that it allows to accurately pin down the isospin two, S--wave $\pi \pi$ scattering length $a_0^2$. On the other hand,…
We properly define off-shell $K\to\pi$ transition amplitudes and use them to extract information for on-shell $K\to\pi\pi$ amplitudes within Chiral Perturbation Theory. At order $p^2$ in the chiral expansion all three parameters of weak…
The gap Delta = 4 pi f_pi ~ 1.2 GeV of spontaneous chiral symmetry breaking is introduced as a scale delineating resonance and continuum regions in the QCD spectral sum rules for vector mesons. Basic current algebra results are easily…