a(1)(1420) peak as the pi f(0)(980) decay mode of the a(1)(1260)

作者：Aceti, F.^*; Dai, L. R.; Oset, E.

来源：PHYSICAL REVIEW D, 2016, 94(9): 096015.

DOI：10.1103/PhysRevD.94.096015

• GAUGE BOSON
• MESON

We study the decay mode of the a(1)(1260) into a pi(+) in p wave and the f(0)(980) that decays into pi(+)pi(-) in s wave. The mechanism proceeds via a triangular mechanism where the a(1)(1260) decays into K*K-, the K* decays to an external pi(+) and an internal K that fuses with the (K) over bar producing the f(0)(980) resonance. The mechanism develops a singularity at a mass of the a(1)(1260) around 1420 MeV, producing a peak in the cross section of the pp 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 a(1)(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.

• 出版日期2016-11-30
• 单位辽宁师范大学; 中国科学院近代物理研究所