D.M. Chew

Inclusive ϱ° production in π−p interactions at 205 GeV/c

Abstract The inclusive ϱ ° production cross section has been measured in the reaction π − p → π + π − X at 205 GeV/ c . We find σ ( ϱ ° ) = 13.5 ± 3.4 mb, with most of the production occuring in the central region. Assuming σ ( ϱ + ) ≈ σ ( ϱ − ) ≈ σ ( ϱ ° ), it is concluded that approximately one-third of the pions at this energy come from ϱ -decay.

An amplitude analysis for the reaction π+ p → π+π−π0 Δ++ at 7 GeV/c☆

Abstract An amplitude analysis for the reaction π+ p → π+π−π0 Δ++ at 7 GeV/c has been performed using the isobar model for the 3π system. The 3π-mass covers the range from 0.82 to 1.90 GeV. We observe strong A2 production. The spin parity of the ω ∗ (1700) is determined to be 3−. No significant A1 production can be seen.

Is there a continuum ambiguity for elastic πN amplitudes

The continuum ambiguity is defined as a phase factor not determined by those amplitude zeros near the physical region that can be directly deduced from the data; such a factor may be approximated by a polynomial whose zeros are far from the physical region. A study of recent TIN partial wave analysis (CUTKOSKY76 and HOHLER78) reveals that such a phase is either null or negligeable; CUTKOSKY76 s amplitude is found similar to that of a partial wave analysis based on Barrelet zeros. We give general arguments based on the notion of peripheral resonances to explain this situation. Our arguments imply that Atkinsons {pi}{sup +}p continuous ambiguity is not relevant to the reliability of Barrelet-zero amplitude analysis.