Evidence for a fourth state related to the threeJPC=2++,π−p→ϕϕnstates explainable by2++glueball production

Abstract

Four separate experiments [A. Etkin et al., Phys. Rev. Lett. 41, 784 (1978).][A. Etkin et al., Phys. Rev. Lett. 49, 1620 (1982).][A. Etkin et al., Phys. Lett. B 165, 217 (1985).][A. Etkin et al., Phys. Lett. B 201, 568 (1988).] observing the OZI forbidden disconnected reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\phi}\ensuremath{\phi}n$ with increasing statistics were consistent. These experiments, very selectively, completely broke down the OZI suppression by three $\ensuremath{\phi}\ensuremath{\phi}$ resonances with ${I}^{G}{J}^{PC}={0}^{+}{2}^{++}$ in the observed mass region 2.038 GeV to 2.600 GeV. The only viable proposed explanation has been that the ${I}^{G}{J}^{PC}={0}^{+}{2}^{++}$ glueball expected in this mass region caused the hard glue in the disconnection to resonate and very selectively break down the OZI suppression for its quantum numbers only. Recently a $pp$ central production spin analysis found that the ${f}_{2}(1950)$ had a dominant decay mode ${f}_{2}(1270)\ensuremath{\pi}\ensuremath{\pi}$ [D. Barberis et al., Phys. Lett. B 471, 440 (2000).]). We consider if it is related to the $\ensuremath{\phi}\ensuremath{\phi}$ resonances, and find that it likely is.