The quark condensate from K(e(4)) decays.

@article{Colangelo2001TheQC,
  title={The quark condensate from K(e(4)) decays.},
  author={G Colangelo and J. Gasser and Heinrich Leutwyler},
  journal={Physical review letters},
  year={2001},
  volume={86 22},
  pages={
          5008-10
        }
}
We show that, independently of the size of the quark condensate, chiral symmetry correlates the two S-wave pipi scattering lengths. In view of this constraint, the new precision data on K(e(4)) decay allow a remarkably accurate determination of these quantities. The result confirms the hypothesis that the quark condensate is the leading order parameter. 

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References

SHOWING 1-10 OF 32 REFERENCES
Low energy theorems as precision tests of QCD
Abstract We work out the low energy expansion of the ππ-scattering amplitude with a method proposed in the preceeding paper. Using the measured D-waves as an input we predict the behaviour of theExpand
Pion-pion scattering at low energy
We present technical details of the evaluation of the elastic ππ scattering amplitude to two loops in chiral perturbation theory. In particular, we elaborate on the renormalization procedure at theExpand
Determination of two-loop ππ scattering amplitude parameters
The chiral expansion of the ππ amplitude to the order of two loops was expressed in terms of six independent parameters in a previous paper: four of these are shown here to satisfy sum rules. TheirExpand
The low energy ππ amplitude to one and two loops
Abstract The low-energy ππ 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 fixedExpand
Chiral perturbation theory to one loop
* in terms of a few constants, which may be identified with the coupling constants of a unique effective low energy Lagrangian. The low energy representation of several Green’s functions and formExpand
$N_f$ dependence of the quark condensate from a chiral sum rule
Abstract. How fast does the quark condensate in QCD-like theories vary as a function of $N_f$ is inferred from real QCD using chiral perturbation theory at order one loop. A sum rule is derived forExpand
Phase-shift analysis of π+π− scattering between 1.0 and 1.8 GeV based on fixed momentum transfer analyticity (II)
Abstract We present our final results for a ππ phase-shift analysis based on extrapolated moments obtained from the 17 GeV/c CERN-Munich experiment on π−p→π+π−n. Compared to our previous publicationExpand
Elastic $\pi\pi$ scattering to two loops
We evaluate analytically the elastic $\pi\pi$ scattering amplitude to two loops in chiral perturbation theory and give numerical values for the two $S$--wave scattering lengths and for the phaseExpand
Exact integral equation for pion-pion scattering involving only physical region partial waves
Abstract We derive an exact relation for ππ scattering which yields the real parts of the ππ partial wave amplitudes al(I)(s) in the region 4m2π ⩽ s ⩽ 60m2π, is given i) the I = 0 and the I = 2 SExpand
QUASI-PARTICLES AND GAUGE INVARIANCE IN THE THEORY OF SUPERCONDUCTIVITY
Ideas and techniques known in quantum electrodynamics have been applied to the Bardeen-Cooper-Schrieffer theoryof superconductivity. In an approximation which corresponds to a generalization of theExpand
...
1
2
3
4
...