Resonant Structure of $\tau\to 3\pi\pi^{0}\nu_{\tau}$ and $\tau\to \omega\pi\nu_{\tau}$ Decays

TL;DR

This paper investigates the resonant structures in tau decays to four pions, analyzing data from the CLEO II experiment to identify intermediate states, measure resonance parameters, and search for second class currents.

Contribution

It provides the first detailed partial wave analysis of the four pion final state in tau decays and sets limits on non-vector current contributions in tau to omega pi decays.

Findings

Resonant structure dominated by omega pi and a1 pi final states.

Extracted mass and width of the rho' resonance.

Established an upper limit on second class current contribution.

Abstract

The resonant structure of the four pion final state in the decay $\tau \to 3\pi\pi^0\nu_\tau$ is analyzed using 4.27 million $\tau^+\tau^-$ pairs collected by the CLEO II experiment. We search for second class currents in the decay $\tau \to \omega\pi\nu_\tau$ using spin-parity analysis and establish an upper limit on the non-vector current contribution. The mass and width of the $\rho'$ resonance are extracted from a fit to the $\tau \to \omega\pi\nu_\tau$ spectral function. A partial wave analysis of the resonant structure of the $\tau \to 3\pi\pi^0\nu_\tau$ decay is performed; the spectral decomposition of the four pion system is dominated by the $\omega\pi$ and $a_1 \pi$ final states.