Backgrounds in the search for Second Class Currents in $\tau$ decays

Abstract

As constructed, the Standard Model does not include genuine Second Class Currents, however these can be induced through the breaking of isospin or charge conjugation. The experimental limits from B-Factories are getting closer to the predictions made for induced Second Class Currents through isospin breaking in the processes $\tau\to\pi\eta^{(\prime)}\nu_\tau$, therefore a more careful analysis of the background in these decays becomes necessary. In this work we analyze the $\tau\to\pi\eta^{(\prime)}\gamma\nu_\tau$ decays as background of the non-radiative process. We find that the radiative processes are very important background for the non-radiative ones whenever the photon escapes detection. Photons cannot be completely excluded since they need to be kept for the identification of the eta and eta' in the final state. However, we find that making appropriate cuts in the energy of the photon, this process can be disregarded as an important background.