A Study of the hadronic resonance structure in the decay tau ---> 3 pi neutrino(tau)

The hadronic structure of the decay of the τ lepton to three charged particles, τ →3 πν τ , is studied using data collected by the DELPHI detector at LEP between 1992 and 1995. The invariant mass of the 3 π system, m 3 π , is fitted using the models of Kühn and Santamaria, Isgur, Morningstar and Reader, and Feindt. The 3 π and π + π − mass spectra are compared with each model. Below m 3π 2 =2.3 GeV 2 , all are in good qualitative agreement. Above m 3π 2 =2.3 GeV 2 , anomalous behaviour is observed, consistent with the existence of a hitherto unseen decay mode of the τ through a radial excitation of the a 1 meson.

electron positron: colliding beams
electron positron: annihilation
Z0: electroproduction
tau: pair production
tau: semileptonic decay
mass spectrum: (3pi)
Dalitz plot
a1(1260): excited state
parametrization
DELPHI

References(24)

Figures(0)

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