Seminar of Hadron Physics

Date and Time: Friday, 22 December 2017, at 11:00 AM

Venue: Blokhintsev Hall (4th floor), Bogoliubov Laboratory of Theoretical Physics

Seminar topic: «τ → f₁π⁻ν_τ decay in the extended Nambu–Jona-Lasinio model»

Speaker: A. A. Pivovarov

Authors: M. K. Volkov, A. A. Pivovarov, A. A. Osipov

Abstract:

Within the framework of the extended Nambu–Jona-Lasinio model, we calculate the matrix element of the τ → f₁(1285)π⁻ν_τ decay and estimate the value of the branching ratio Br(τ → f₁π⁻ν_τ) = 4.0 × 10⁻⁴. The two types of contributions are considered: the contact interaction, and the axial-vector I^G(J^PC) = 1⁻(1⁺⁺) resonance exchange. The latter includes the ground a₁(1260) state, and its first radially excited state, a^|₁(1640). The corrections caused by the πa₁ transition are taken into account. The result is in a good agreement with known phenomenological data Br_exp(τ → f₁π⁻ν_τ) = (3.9 ± 0.5) × 10⁻⁴.