25-29 September 2017
Salamanca, Spain
Europe/Zurich timezone

The a1(1420) peak as the special decay mode of the a1(1260)

26 Sep 2017, 15:55
Aula 2.3

Aula 2.3

Talk Analysis tools Analysis tools


Prof. Lianrong Dai (Liaoning Normal university)


I will present the recent work [Phys Rev D94(2016) 096015] about the a1(1420) peak which is experimentally and theoretically interesting. We study the decay mode of the a1(1260) into a pi+ in p-wave and the f0(980) that decays into pi+ pi- in s-wave. The mechanisms proceeds via a triangular mechanism where the a1(1260) decays into Kbar K, the K decays to an external pi+ and an internal K that fuses with the Kbar to produce the f0(980) resonance. The mechanism develops a singularity at a mass of the a1(1260) around 1420 MeV, producing a peak in the cross section of the pi p reaction, used to generate the mesonic final state, which provides a natural explanation of all the features observed in the COMPASS experiment, where a peak observed at this energy is tentatively associated to a new resonance called a1(1420). On the other hand, the riangular
singularity studied here gives rise to a remarkable feature, where a peak is seen for a certain decay channel of a resonance at an energy about 200 MeV higher than its nominal mass.

Primary authors

Prof. Lianrong Dai (Liaoning Normal university) Dr Francesca Aceti Prof. Eulogio Oset

Presentation Materials

There are no materials yet.