A comparative investigation of low mass π+ω and K −ω systems at various energies

Abstract

A comparison is made of the properties and production mechanisms of the π + ω and K − ω systems produced in the reactions π +p → π + ωp at 4, 5, 8 and 16 GeV/ c and K − p → K − ωp at 10 and 16 GeV/ c. In the π + ω case apeak is observed at 1.23 GeV (the B meson), while the K − ω mass distribution has a threshold enhancement. The cross section of the low mass (<2.0 GeV) π + ω system falls as p lab −2, while that of the low mass (<2.0 GeV) K − ω system is almost constant with energy, indicating diffractive production of the K − ω system, but not of the πω system. Using a modified version of the Illinois partial-wave analysis program, it is found that the K − ω system is dominantly produced in the J P = 1 + state with small contributions of 0 − and 2 +, mainly by natural parity exchange - as is found for reactions such as K −p → (K − π + π −)p which are predominantly diffractive. For the π + ω system in the B mass region, J P = 1 + states, produced mainly by natural parity exchange are found; the contributions of 0 −P, 1 −P, 2 −P and 2 +D are consistent with zero. The 1 +D state occurs in the π + ω case but not in the K − ω system, nor in the K ππ − system produced in the K −p → K ππp reaction.