Physical review. D, 2016-11, Vol.94 (9)
2016
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Details
- Autor(en) / Beteiligte
- Titel
- a1(1420) peak as the πf0(980) decay mode of the a1(1260)
- Ist Teil von
- Physical review. D, 2016-11, Vol.94 (9)
- Ort / Verlag
- College Park: American Physical Society
- Erscheinungsjahr
- 2016
- Quelle
- Alma/SFX Local Collection
- Beschreibungen/Notizen
- We study the decay mode of the a1(1260) into a π+ in p wave and the f0(980) that decays into π+π− in s wave. The mechanism proceeds via a triangular mechanism where the a1(1260) decays into K*K¯, the K* decays to an external π+ and an internal K that fuses with the K¯ producing 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 πp 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 triangular 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.