2018 Impact factor 4.843
Particles and Fields
Eur. Phys. J. C 11, 359-363
DOI 10.1007/s100529900192

Comparing the broken $U3 \times U3$ linear sigma model
with experiment

N.A. Törnqvist

Physics Deptartment University of Helsinki, PB9, 00014 Helsinki, Finland

Received: 9 June 1999 / Published online: 14 October 1999

Abstract
The linear $\sigma$ model with broken $U3 \times U3$ is compared with data of the lightest scalar and pseudoscalar mesons. When 5 of the 6 parameters are fixed by the pseudoscalar masses and decay constants, one finds that, already at the tree level, one has a reasonable description for the 4 scalar masses, describing mixing and up to 8 trilinear couplings of lightest scalars, taken as $a_0(980),\ f_0(980),\ \sigma(\approx 500) $ and K*0(1430 ). This clearly indicates that these scalars are the chiral partners of the $\pi,\ \eta,\ \eta ',\ K$, and this strongly suggests that they, like the latter, are (unitarized) $q \bar q$ states.


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