Dresden 2013 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 73: Hadronenstruktur und -spektroskopie
HK 73.2: Talk
Thursday, March 7, 2013, 17:15–17:30, HSZ-105
Propagator poles and an emergent stable state below threshold: general discussion and the E(38) state — •Thomas Wolkanowski and Francesco Giacosa — Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, D-60438 Frankfurt, Germany
Employing a simple quantum field-theoretical model which describes the decay of a scalar state into two (pseudo)scalar ones, we investigate the poles of the scalar propagator. Besides the expected resonance pole in the lower half-plane of the second Riemann sheet, we find – for a sufficiently large coupling constant – an additional pole on the first sheet below threshold, corresponding to a dynamically generated stable state. We then perform a numerical study for a hadronic system involving a scalar seed state that couples to pions. It is clarified under which conditions a stable state below the two-pion threshold can emerge. In particular, in reference to the recent claim of a novel scalar boson with mass 38 MeV (termed E(38)), we explore the case of a stable state with such a mass. Our findings suggest that the resonance f0(500) and the stable state E(38) could be interpreted as two different manifestations of one and the same ’object’.