tau -> pi pi pi nu_tau decays and the a1(1260) off-shell width revisited

DANIEL GOMEZ DUMM; PABLO ROIG; ANTONIO PICH; JORGE PORTOLES

PHYSICS LETTERS B

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2010 vol. 685 p. 158 - 164

0370-2693

The tau -> pi pi pi nu_tau decay is driven by the hadronization of the axial-vector current. Within the resonance chiral theory, and considering the large-NC expansion, this process has been studied in Ref. [1] (D. Gómez Dumm, A. Pich, J. Portolés, 2004). In the light of later developments we revise here this previous work by including a new off-shell width for the lightest a1 resonance that provides a good description of the tau -> pi pi pi nu_tau spectrum and branching ratio. We also consider the role of the rho(1450) resonance in these observables. Thus we bring in an overall description of the tau -> pi pi pi nu_tau process in excellent agreement with our present experimental knowledge.