Model-dependent radiative corrections to revisited

Abstract

The long-distance electromagnetic radiative corrections to τ − → π − π 0 ντ are re-evaluated. A meson dominance model is used to describe the emission of real photons in this decay. Results obtained for the hadronic spectrum and the decay rate in photon inclusive reactions are compared with previous calculations based on the chiral resonance theory. Independent tests in τ → ππνγ that can help to validate the predictions of one of the two models are briefly discussed.

Long distance radiative corrections to the decayτ−→π−π0ντ

“…Equivalently, if we exclude only the contributions involving an intermediate a 1 (1260) state (Figures 2.e, 2.f, 2.j and 2.k of ref. [11]), the values obtained for G EM (t) almost overlap the solid line in Figure 1. The simple formula (x ≡ t/m 2 τ ):…”

“…Given all these considerations, in ref. [11] we have used a meson dominance model to study the effects of model-dependent contributions in different observables associated with radiative τ 2π decays. We have found that some of these observables exhibit important differences with respect to the results of ref.…”

“…We have checked that the piece in this term coming from modelindependent bremsstrahlung is correct, and we have focused on the evaluation of the second term of eq. (6) based on the model discussed in our previous work [11].…”

“…This discrepancy in model-dependent terms arise almost completely from the contribution of the ω(782) intermediate state in radiative τ 2π decays (Figure 2.g, of ref. [11]). To confirm this, we plot in Figure 2 our results for G EM (t) obtained when we exclude the diagram containing the ω(782) vector meson (dotted line).…”

“…In this paper we evaluate the model-dependent contributions to long-distance radiative corrections in τ 2π decays based on a meson dominance model that was used in ref. [11] to study the corresponding radiative tau decays (τ → ππνγ). We focus here on the long-distance radiative corrections of O(α) to the di-pion spectrum and to the decay rate of τ 2π decays.…”