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

TL;DR

This paper analyzes the background effects of radiative tau decays involving eta and eta' mesons, emphasizing the importance of photon detection and energy cuts to distinguish these from non-radiative processes in the search for Second Class Currents.

Contribution

It provides a detailed analysis of radiative tau decay backgrounds, highlighting the role of photon energy cuts in experimental searches for Second Class Currents.

Findings

Radiative tau decays are significant backgrounds when photons are undetected.

Proper photon energy cuts can effectively reduce this background.

Background analysis aids in more accurate searches for Second Class Currents.

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.