München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 21: Postersitzung

HK 21.21: Poster

Dienstag, 21. März 2006, 15:30–17:00, P

Investigation of a₀⁺(980) production in pp→ dπ⁺η with WASA at COSY^⋆ — •P. Fedorets¹, M. Büscher¹, and V. Chernyshev² — ¹Forschungszentrum Jülich, Germany — ²ITEP, Moscow, Russia

The WASA facility is currently being installed at COSY-Jülich. We have carried out simulations in order to check the possibility to measure the reaction pp→da₀⁺→ dπ⁺η with the decay channel η→γγ with WASA at a COSY beam energy of T=2.65 GeV by detection of deuterons in the forward detector and pions and photons in the central detector. The dπ⁺η final state will be identified by the reconstructing the η via the γγ invariant mass and the deuteron as the π⁺η missing mass. The a₀⁺(980) resonance is observed as a peak in the invariant mass (π⁺γγ).

For an estimate of the pp→da₀⁺→ dπ⁺η(→ 2γ) cross section we have used data for another a₀⁺ decay channel, pp → da₀⁺→ dK⁺K^0, recently measured with the ANKE spectrometer at COSY for the same beam energy: the estimated count rate is ≈ 13000 day⁻¹.

The simulations further show that the main expected background reaction pp → pnπ⁺η with misidentification of protons as deuterons can be suppressed down to a signal/background ratio ≈ 1.

^⋆Supported by EC, DFG, RFFI, PI.