Münster 2002 – scientific programme
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HK: Physik der Hadronen und Kerne
HK 46: Electromagnetic and Hadronic Probes VI
HK 46.6: Talk
Thursday, March 14, 2002, 17:45–18:00, D
Investigation of the a0+(980) Resonance at ANKE — •V. Kleber — Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich
In a recent ANKE beam time at COSY Jülich a first experiment on the production of scalar mesons in pp collisions was performed. The goal of this experiment is to investigate the a0+(980) resonance, a candidate for the scalar meson nonet, in the reaction pp → da0+.
The a0(980) is known to decay in KK, πη and 2γ. At ANKE the deuteron and the decay K+ or π+ are detected. The mesons are identified by TOF and energy loss, the coincident deuterons by their TOF relative to the mesons. Subsequently the a0+(980) is investigated with a missing mass analysis.
In case of a K+ and a deuteron a clean sample of dK+K0 events is obtained due to energy and strangeness conservation. In the missing mass distribution m(pp,d) a narrow structure is observed mainly given by the KK production threshold (mmin=991 MeV) and the COSY beam energy of T=2.65 GeV (mmax=1038 MeV).
In the missing mass distribution m(pp,dπ+) a clear peak from η mesons on a broad background is seen as well as a shoulder in the distribution m(pp,d) at the a0(980) mass which reveals a peak structure after background subtraction.