%0 Journal Article
%T Triangle singularity in tau(-) -> nu(tau)pi(-) f(0)(980) (a(0)(980)) decays
%A Dai, L. R.
%A Yu, Q. X.
%A Oset, E.
%J Physical Review D
%D 2019
%V 99
%N 1
%I Amer Physical Soc
%@ 2470-0010
%G English
%F Dai_etal2019
%O WOS:000457697500012
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=3905), last updated on Tue, 19 Feb 2019 08:36:16 +0000
%X We study the triangle mechanism for the decay tau(-) -> nu(tau)pi(-) f(0)(980) with the f(0)(980) decaying into pi(+) pi(-). The mechanism for this process is initiated by tau(-) -> nu K-tau*(0) K- followed by the K*(0) decay into pi K--(+), then the K- K+ produce the f(0)(980) through a triangle loop containing K* K+ K- which develops a singularity around 1420 MeV in the pi f(0)(980) invariant mass. We find a narrow peak in the pi(+) pi(-) invariant mass distribution, which originates from the f(0)(980) amplitude. Similarly, we also study the triangle mechanism for the decay tau -> nu pi(-) a(0)(980), with the a(0)(980) decaying into pi(0)eta.The formalism leads to final branching ratios for pi(-) f(0)(980) and pi(-) a(0)(980) of the order of 4 x 10(-4) and 7 x 10(-5), respectively, which are within present measurable range. Experimental verification of these predictions will shed light on the nature of the scalar mesons and on the origin of the "a(1)(1420)" peak observed in other reactions.
%R 10.1103/PhysRevD.99.016021
%U https://arxiv.org/abs/1809.11007
%U https://doi.org/10.1103/PhysRevD.99.016021
%P 016021-13pp