Double resonance in Dalitz plot of M_pΛ–M_KΛ in DISTO data on p + p → p + Λ + K⁺ at 2.85 GeV

The X(2265) resonance was previously observed in DISTO data of p + p → p + Λ + K⁺ at 2.85 GeV on an attempt of searching for the kaonic nuclear state K⁻pp → p + Λ. In the present paper we report an additional finding, namely, a double-resonance-type phenomena, not only with a peak at M(pΛ) = 2265 MeV/c² but also a broad bump at M(K⁺ Λ) ∼ 1700 MeV/c². This 'double-resonance' zone is expressed as XY(2265, 1700). The latter bump may result from nearby nucleon resonances, typically N^*(1710), as well as by attractive K⁺-Λ final-state interaction. We point out that this double resonance XY(2265, 1700) as seen in DISTO at 2.85 GeV cannot be populated kinematically in a HADES experiment at 3.5 GeV. (author)