Evidence of new physics in radiative pion decay and its effect in other processes

by Mihail Chizhov (Sofia University)

Friday 4 Jun 2004, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

The recent PIBETA results confirm at 9σ level the deficit of events in the radiative pion decay in the same kinematic region already observed at the ISTRA facility. In order to explain this anomaly, an introduction of new centi-weak tensor interactions is necessary. Such interactions inevitably affect other electroweak processes. Although in most of them they lead to negligible contributions due to their different chiral structure from V-A interactions, in some particular cases their effect can be noticeable. An example of such effects is the excess in pion production in τ-decay which explains the discrepancy with CVC prediction. The high-precision ongoing experiments at PSI and TRIUMF are also capable of detecting the effects of the new tensor interactions in the pure lepton decays of the polarized muons at a level of 3σ and 8σ, correspondingly.