Eur. Phys. J. A (2006) 29: 245-251
https://doi.org/10.1140/epja/i2006-10087-7

Hadron Physics

Scalar-isovector K¯ production close to threshold

¹ High Energy Physics Department, Petersburg Nuclear Physics Institute, 188350, Gatchina, Russia
² Institut für Kernphysik, Forschungszentrum Jülich, 52425, Jülich, Germany
³ Institut für Kernphysik, Universität zu Köln, 50937, Köln, Germany
⁴ Institute for Theoretical and Experimental Physics, Bolshaya Cheremushkinskaya 25, 117218, Moscow, Russia
⁵ Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Russia
⁶ Institute for Nuclear Research, 60th October Anniversary Prospect 7A, 117312, Moscow, Russia
⁷ Institute of Nuclear Physics, Radzikowskiego 152, 31342, Cracow, Poland
⁸ Institut für Kernphysik, Universität Münster, 48149, Münster, Germany
⁹ Helmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität Bonn, Nußallee 14-16, 53115, Bonn, Germany
¹⁰ The Andrzej Sołtan Institute for Nuclear Studies, 05400, Świerk, Poland

Received: 18 May 2006
Accepted: 21 August 2006
Published online: 12 September 2006

Abstract

The reaction pp → dK ⁺¯ has been investigated at excess energies Q = 47.4 and 104.7MeV above the K ⁺¯ threshold at COSY Jülich. Coincident dK⁺ pairs were detected with the ANKE spectrometer, and subsequently ∼ 2000 events with a missing ¯ invariant mass were identified, which fully populate the Dalitz plot. The joint analysis of invariant mass and angular distributions reveals s-wave dominance between the two kaons, in conjunction with a p-wave between the deuteron and the kaon pair, i.e. K¯ production via the a ₀ ⁺(980) channel. Integration of the differential distributions yields total cross-sections of σ(pp → dK ⁺¯) = (38±2_stat±14_syst)nb and (190±4_stat±39_syst)nb for the low and high Q value, respectively.