Formation of the S = -1 resonance X(2265) in the reaction pp → X+K+ at 2.50 and 2.85 GeV

Analyzing DISTO data of pp → p Λ K + at T p = 2.50 and 2.85GeV to populate a previously reported X (2265) -resonance with M x = 2267 MeV/c 2 and Γ x = 118 MeV at 2.85GeV, we found that the yield of X (2265) at 2.50GeV is much less than that at 2.85GeV (less than 10%), though it is expected from a kinematical consideration to be produced as much as 33% of that at 2.85GeV. The small population of X (2265) at 2.50GeV is consistent with the very weak production of Γ(1405) at the same incident energy toward its production threshold, thus indicating that Γ(1405) plays an important role as a doorway state for the formation of X (2265).