Observation of a narrow scalar meson at 1450 MeV in the reaction pp → pƒ(π+π−π+π−)ps at 450 GeV/c using the CERN Omega spectrometer

Abstract The reaction pp → pƒ(π + π − π + π − )p s has been studied at 450 GeV/ c in an experiment designed to search for gluonic states. In addition to the well known ƒ 1 (1285) , the π + π − π + π − mass spectrum shows evidence for two states pre only observed by the WA76 experiment, the X(1450) and X(1900). An analysis of the X(1450) shows that it is a relatively narrow state ( Γ = 56 ± 12 MeV) with I ( J PC ) = 0(0 ++ ) which decays to ϱ 0 π + π − . The X (1900) could either b single broad state ( Γ = 370±70 MeV) with I ( J PC ) = 0(2 ++ ) or possibly separate states.