Search for non-strange exotic mesons produced via baryon exchange

Abstract

Negative results on backward production, via baryon exchange, of exotic non-strange mesons are presented. The reactions π −p→p forward X −and π −n→ p forward X −− have been studied with a 12 GeV/ c π − beam in the Omega spectrometer at CERN. No resonant peak in X→ p p π −, p p π −π −, p p π −π 0,π +π −π −π 0 has been seen. The upper limits obtained on cross sections for exotic meson production X → N N π, N N π, 4π are lower than the ϱ − backward production cross section in the π −p→p ϱ − reaction; this result seems to contradict the predictions of the two-component duality model. Compared to already published experiments in the search for exotics produced via baryon exchange, the sensitivity of this experiment is increased by an order of magnitude.