Radiative corrections to the charged pion-pair production process π − γ → π + π − π − at low energies

Measurement of Γ ( K S → π + π − ( γ ) ) / Γ ( K S → π 0 π 0 )

We have measured the ratio R S = Γ(KS → π π(γ))/Γ(KS → π π) with the KLOE detector at the DAΦNE ee collider. This measurement is fully inclusive with respect to the ππγ final state. The sample of over 10 two-pion decays of tagged KS mesons allows a statistical error as low as ∼ 0.1% to be obtained. The accuracy is limited by systematic uncertainties, which are estimated primarily from data. We ...

π-N charge exchange and π +-π 0 scattering at low energies ∗

Electromagnetic corrections to γπ ± → π 0 π ±

The amplitude for the anomalous transitions γπ → ππ is analyzed within Chiral Perturbation Theory including electromagnetic interactions. The presence of a t-channel one-photon exchange contribution induces sizeable O(e2) corrections which enhance the cross-section in the threshold region and bring the theoretical prediction into agreement with available data. In the case of the crossed reactio...

η → π + π − π 0 γ in Chiral Perturbation Theory

→ π + π − ) measurement via radiative return method ∗

The radiative return method [1] (look [2] for a short introduction) is a powerful tool in the measurement of σ(ee → hadrons), crucial for predictions of the hadronic contributions to aμ, the anomalous magnetic moment of the muon, and to the running of the electromagnetic coupling from its value at low energy up to MZ (for recent reviews look [3, 4, 5]). Due to a complicated experimental setup, ...