A Study of the Reactions π^±p → π^±π^+π^-π^op and π^±p → π^±π^+π^+π^-n at P_(lab) = 14 GeV/c Using a Triggered Hybrid Bubble Chamber

Citation

Nagy, Frank Joseph (1980) A Study of the Reactions π^±p → π^±π^+π^-π^op and π^±p → π^±π^+π^+π^-n at P_(lab) = 14 GeV/c Using a Triggered Hybrid Bubble Chamber. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/q42m-vd27. https://resolver.caltech.edu/CaltechTHESIS:05192017-102645117

Abstract

We have studied the reactions π^±p → π^±π⁺π^-π^op and π^±π⁺π⁺π^-n at a beam momentum of 14 GeV/c. A bubble chamber with a downstream wire spark chamber spectrometer was used to record the data. The bubble chamber camera was triggered by identifing inelastic events in an online computer using data from the downstream spectrometer. The film taken represents an exposure of about 80 events/microbarn for the π⁺ data and 70 events/microbarn for the π^- data.

We find these reactions to be very rich in subprocesses involving baryon and meson resonances. The invariant mass spectra are presented and estimates of the cross sections for the production of known baryon and meson resonances are given.

The reactions π^±p → π^±ω^op provided more evidence for the existence of an N^* resonance with mass 1789±5 MeV and width 81±9 MeV which decays into ω^op. Using previously published data along with our results, we find that the production cross section of this N^* is independent of s. Studies of the angular distributions raise questions about the validity of the spin-parity analyses of this N^* done so far.

We have studied the processes π^±p → π^±η^op in the relatively unexplored region of low |t_ππ| and small η^op mass. We found that the π⁺η^op cross section is about twice the π^-η^op cross section in this region. The η^op mass spectrum for the π⁺ data shows an enhancement at about 1600 MeV while the π^- data show no evidence of a peak in the η^op mass spectrum.

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