Study of s-Channel and t-Channel Helicity Conservation in the Diffractive Part of the Reaction pi+- p --> pi (n pi) at 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Heidelberg collaboration Grässler, H. ; Kirk, H. ; Otter, G. ; et al.
Nucl.Phys.B 95 (1975) 1-11, 1975.
Inspire Record 99495 DOI 10.17182/hepdata.31974

By means of an isospin analysis of the reaction π ± p→ π (N π ) at 16 GeV/ c we have determined the decay angular distributions of the N π system with I= 1 2 produced by isospin zero exchange. Helicity conservation is not observed in the t -channel for the N π mass region below 1.6 GeV, where diffraction dissociation of the proton is supposed to dominate. There are indications for approximate t -channel helicity conservation for N ∗ (1690) production. In the helicity frame, the experimental data are not in agreement with s -channel helicity conservation over the whole N π mass range investigated. Thus the diffractive process N→N π differs both from the process N→N ππ (or π → πππ and K→K ππ ) which approximately conserves t -channel helicity and from the elastic scattering N→N which conserves helicity in the s -channel.

2 data tables

No description provided.

FIT TO ISOSPIN HALF NUCLEON RESONANCE PRODUCTION WITH ISOSPIN ZERO EXCHANGE.


Spin-Parity Analysis of the Diffractively Produced Low Mass n pi System in the Reaction pi+- p --> pi+- (n pi)+ at 16-GeV/c

The Aachen-Berlin-Bonn-CERN collaboration Otter, G. ; Rudolph, G. ; Wieczorek, H. ; et al.
Nucl.Phys.B 130 (1977) 349, 1977.
Inspire Record 119192 DOI 10.17182/hepdata.35244

The dominant partial waves of the diffractively produced N π system at low Nπ masses (⩽ 1.4 GeV) are determined in the reactions π ± p → π (N π ) at 16 GeV/ c . A satisfactory description of our data can only be obtained by strong contributions of both a 1 2 − S-wave and a 3 2 + P-wave, violating the Gribov-Morrison rule. Spin and parity of the diffractively produced states are found from the interference between diffraction and Δ (1236) production. The interference term is obtained by an isospin analysis.

2 data tables

No description provided.

<NUCLEON PION> MASS DEPENDENCE.


Cross-Section Measurement for Nonstrange Final States and Single Pion Production in pi+ p Interactions at 3.6-GeV/c

Macnaughton, J. ; Butler, W.R. ; Coyne, D.G. ; et al.
Phys.Rev.D 15 (1977) 1832-1845, 1977.
Inspire Record 124169 DOI 10.17182/hepdata.24652

Cross sections are presented for all final states without strange-particle production. Contributions to single-pion production are found from (i) Δ(1238)π, (ii) ρ+p, (iii) nucleon diffractive dissociation into Nπ, (iv) N*(1688)π+, and (v) "phase space." Processes (i), (ii), and (iii) are studied in some detail taking into account overlaps between the various subchannels.

10 data tables

No description provided.

'JM'.

'JM'. USING DATA WITH 1.12 < M(P PI+) < 1.32 GEV AND COS(P PI DECAY ANGLE IN JACKSON FRAME) < 0.

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