München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 9: Elektromagnetische und Hadronische Sonden

HK 9.4: Vortrag

Montag, 20. März 2006, 17:30–17:45, G

Single Pion Productions at 400 MeV: agreements and disagreements with previous results — •E. Doroshkevich, H. Clement, K. Ehrhardt, A. Erhardt, and G.J. Wagner — Physikalisches Institut, Uni. Tuebingen

The single-pion production channels pp → dπ⁺, pp → pnπ⁺ and pp→ ppπ⁰ have been measured at COSY at 950 MeV/c (T_p=397 MeV) by using the short version of the TOF spectrometer. Particle identification and 4-momenta of charged particles have been obtained by measurements of ToF, E and pixel coordinates. Neutron detection with an efficiency of about 30% has been achieved by a hit in the calorimeter accompanied with no hits in the preceding fiber and quirl hodoscope layers.

Whereas the pnπ⁺ channel is strongly influenced by Δ excitation it is heavily suppressed in the ppπ⁰ channel. For the pnπ⁺ channel our data agree with previous PROMICE/WASA data [1]. But for the ppπ⁰ channel our data for angular distributions, in particular for π⁰, disagree substantially from PROMICE/WASA data [2] and from the prediction of IUCF phase shift results [4]. Our data, however, agree with CELSIUS-WASA results [3] as well with predictions of Hanhart et.al. [5], which differ from the IUCF phase shifts in the Δ-dependent Pp waves.

[1] R. Bilger et al., Phys. Lett. B446 (1999) 179

[2] R. Bilger et al., Nucl. Phys. A693 (2001) 633

[3] S.Keleta Licentiate Thesis 2004

[4] H.O.Meyer et.al.Phys.Rev. C63(2001)064002, C65(2002)024003

[5] P.Deepak, J.Haidenbauer, C.Hanhart Phys.Rev.C72(2005)024004

* - supported by BMBF(06TU201), Eur.Grad.Kolleg, COSY-FFE