2012/09/28 by F. Aceti, Wei-Hong Liang, W. H. Liang +4 · 7 citations
Physics and Astronomy · #Bar (unit) #High-Energy Particle Collisions Research #Isospin #Meson #Mixing (physics) #Particle physics #Particle physics theoretical and experimental studies #Physics #Production (economics) #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.86.114007
arxiv created 2012/09/28 · openalex publication_date 2012/12/04 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We make a theoretical study of the \ensuremathη(1405)\ensuremath→\ensuremathπ0f0(980) and \ensuremathη(1405)\ensuremath→\ensuremathπ0a0(980) reactions with an aim to determine the isospin violation and the mixing of the f0(980) and a0(980) resonances. We make use of the chiral unitary approach where these two resonances appear as composite states of two mesons, dynamically generated by the meson-meson interaction provided by chiral Lagrangians. We obtain a very narrow shape for the f0(980) production in agreement with a BES experiment. As to the amount of isospin violation, or f0(980) and a0(980) mixing, assuming constant vertices for the primary \ensuremathη(1405)\ensuremath→\ensuremathπ0KK and \ensuremathη(1405)\ensuremath→\ensuremathπ0\ensuremathπ0\ensuremathη production, we find results which are much smaller than found in the recent experimental BES paper, but consistent with results found in two other related BES experiments. We have tried to understand this anomaly by assuming an I=1 mixture in the \ensuremathη(1405) wave function, but this leads to a much bigger width of the f0(980) mass distribution than observed experimentally. The problem is solved by using the primary production driven by \ensuremathη^\ensuremath'\ensuremath→K*K followed by K*\ensuremath→K\ensuremathπ, which induces an extra singularity in the loop functions needed to produce the f0(980) and a0(980) resonances. Improving upon earlier work along the same lines, and using the chiral unitary approach, we can now predict absolute values for the ratio \ensuremathΓ(\ensuremathπ0,\ensuremathπ+\ensuremathπ^\ensuremath-)/\ensuremathΓ(\ensuremathπ0,\ensuremathπ0\ensuremathη) which are in fair agreement with experiment. We also show that the same results hold if we had the \ensuremathη(1475) resonance or a mixture of these two states, as seems to be the case in the BES experiment.