2015/01/19 by Jean-Louis Basdevant, Basdevant, Jean-Louis, Edmond L. Berger +1 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #hep-ph
paper · pdf · doi:10.48550/arxiv.1501.04643
11 pages, 9 figures
arxiv created 2015/01/19 · openalex publication_date 2015/01/19 · arxiv updated 2015/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The high statistics COMPASS results on diffractive dissociation πN → πππN suggest that the isospin I=1 spin-parity JPC= 1++ a1(1260) resonance could be split into two states: a1(1260) decaying into an S-wave ρπ system, and a1^′(1420) decaying into a P-wave f0(980)π system. We analyse the reaction by incorporating our previous treatment of resonant re-scattering corrections in the Drell-Deck forward production process. Our results show that the COMPASS results are fully consistent with the existence of a single axial-vector a1 resonance. The characteristic structure of the production process, which differs in the two orbital angular momentum states, plays a crucial role in this determination. Provided the theoretical analysis of the reaction is done in a consistent manner, this single resonance produces two peaks at different locations in the two channels, with a rapid increase of the phase difference between their amplitudes arising mainly from the structure of the production process itself, and not from a dynamical resonance effect. In addition, this analysis clarifies questions related to the mass, width, and decay rates of the a1 resonance.