We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low-energy e + e − colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on τ decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and τ decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.

In this paper we document the modifications introduced to the previous version of the resonance chiral Lagrangian current [Phys. Rev. D 86, 113008 (2012)] of the AE ! AE AE Ç decay which enable the one-dimensional distributions measured by the BABAR Collaboration to be well modeled. The main change required to model the data is the addition of the resonance. Systematic errors, theoretical and experimental ones, limitations due to fits of one-dimensional distributions only, and resulting difficulties and statistical/systematic errors for fitted parameters are addressed. The current and fitting environment is ready for comparisons with the fully exclusive experimental data. The present result for AE ! AE AE Ç is encouraging for work on other decay modes and resonance chiral Lagrangian based currents.

In the present paper we describe the set of form factors for hadronic τ decays based on Resonance Chiral Theory. The technical implementation of the form factors in FORTRAN code is also explained. It is shown how it can be installed into TAUOLA Monte Carlo program. Then it is rather easy to implement into software environments of not only Belle and BaBar collaborations but also for FORTRAN and C++ applications of LHC. The description of the current for each τ decay mode is complemented with technical numerical tests. The set is ready for fits, parameters to be used in fits are explained. Arrangements to work with the experimental data not requiring unfolding are prepared. Hadronic currents, ready for confrontation with the τ decay data, but not yet ready for the general use, cover more than 88 % of hadronic τ decay width.

We have developed a phenomenological approach which describes very well the π 0 , η and η ′ meson production in the two-photon interactions. The simultaneous description of the π 0 , η and η ′ meson two-photon form factors is consistent with data in the space-like region. The obtained form factors are implemented in the event generator EKHARA and the simulated cross sections are presented. Uncertainties in the measured form factors coming from the model dependence in Monte Carlo simulations are studied. The model predictions for the form factor slopes at the origin are given and the high-Q 2 limit is also discussed.

We study, at leading order in the large number of colours expansion and within the Resonance Chiral Theory framework, the odd-intrinsic-parity e + e − → π + π − (π 0 , η) crosssections in the energy regime populated by hadron resonances, namely 3 m π < ∼ E < ∼ 2 GeV. In addition we implement our results in the Monte Carlo generator PHOKHARA 7.0 and we simulate hadron production through the radiative return method.