Peak locations and relative phase of different decay modes of the a₁ axial vector resonance in diffractive production

2015/04/22 by Jean-Louis Basdevant, Edmond L Berger
Physics and Astronomy · #hep-ph

paper · pdf · doi:10.1103/physrevlett.114.192001

published as Phys Rev Lett 114, 192001 (2015) · 4 pages, 4 figures, to be published in Physical Review Letters. arXiv admin note: substantial text overlap with arXiv:1501.04643

arxiv created 2015/04/22 · arxiv updated 2015/05/14

Abstract

We show that a single I=1 spin-parity J^PC= 1⁺⁺ a₁ resonance can manifest itself as two separated mass peaks, one decaying into an S-wave ρπ system and the second decaying into a P-wave f₀(980)π system, with a rapid increase of the phase difference between their amplitudes arising mainly from the structure of the diffractive production process. This study clarifies questions related to the mass, width, and decay rates of the a₁ resonance raised by the recent high statistics data of the COMPASS collaboration on a₁ production in πN → πππN at high energies.

Citations

• The twofold emergence of the a₁ axial vector meson in high energy hadronic production