There is no κ(900) Original Research Article

In the I=0 sector there are more scalar mesons than can fit in one View the MathML source nonet. Consequently, many have claimed that there is in fact more than one multiplet, perhaps both View the MathML source and View the MathML source. Such proposals require the existence of at least two strange isodoublets (and their antiparticles). The current PDG tables list just one state, the View the MathML source, while fits to data with Breit–Wigner forms and variable backgrounds can accommodate a κ(900), too. Whether a state exists in the spectrum of hadrons is not a matter of ability to fit data along the real energy axis, but is completely specified by the number of poles in the complex energy plane. Here we perform as model-independent an analytic continuation of the LASS πK scattering results between 825 MeV and 2 GeV as presently possible to determine the number and position of resonance poles. We find that there is a View the MathML source, but noκ(900). The LASS data cannot rule out the possibility of a very low mass κ well below 825 MeV.