PRISM Plot Analysis of the Reaction pi+ p --> p pi+ pi+ pi- at 16-GeV/c

The AACHEN-BERLIN-BONN-CERN-CRACOW-HEIDELBERG-WARSAW collaboration Deutschmann, M. ; Kirk, H. ; Sixel, P. ; et al.
Nucl.Phys.B 99 (1975) 397-419, 1975.
Inspire Record 104134 DOI 10.17182/hepdata.35967

We have analysed the reaction π + p → pπ + π + π − at 16 GeV/c by means of the prism plot analysis (PPA) as proposed by Pless et al. We have separated ten reaction channels contributing to the final state pπ + π + π − and present the results in terms of partial and differential cross sections, invariant mass and decay angular distributions. We show that the PPA is a self-controlling method which is demonstrated by the emergence of a broad (3π) + enhancement around 1800 MeV decaying into ρ 0 π + .

1 data table

PARTIAL CROSS SECTIONS FOR THE (P PI+ PI+ PI-) FINAL STATE.


Partial Wave Analysis of the (pi+ pi+ pi-) System Through the Region of the A3 Meson

Thompson, G. ; Badewitz, R.C. ; Gaidos, J.A. ; et al.
Nucl.Phys.B 69 (1974) 381-398, 1974.
Inspire Record 760 DOI 10.17182/hepdata.32348

A recent spin-parity analysis of the π + π + π − system formed opposite a proton and a coherent deuteron by incident 13 GeV/ c 2 π + mesons, is extended to a three-pion mass of 1.9 GeV/ c . Relative proportions of the contributing partial waves are presented, from threshold, and the A 3 region is discussed in detail. Contrary to results with the (3 π ) − system, a change in phase is noted for the 2 − amplitude decaying to f 0 π + via am S-wave.

7 data tables

FOR A3+ DEFINED AS 2+ S-WAVE WITH 1.5 < M(3PI) < 1.8 GEV).

CONSTRAINT IMPLIES RHO(11) + RHO(1-1) = 0.

CONSTRAINT IMPLIES RHO(11) + RHO(1-1) = 0.

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Observation of an A3 Amplitude Phase Change

Thompson, G. ; Badewitz, R.C. ; Gaidos, J.A. ; et al.
Phys.Rev.Lett. 32 (1974) 331, 1974.
Inspire Record 772 DOI 10.17182/hepdata.21334

A spin and parity decomposition is presented of the (π+π+π−) final state formed opposite a proton by incident 13-GeV/c π+ mesons. The A3 enhancement is identified as the 2− amplitude decaying to f0π+ via an S wave. A change in relative phase is noted between the 2−S amplitude and the other principal contributions; this is not incompatible with analyses of the (3π)− system. The method employs the University of Illinois three-body partialwave analysis program.

1 data table

A3+ DEFINED AS JP=2- S-WAVE.


Cross sections for resonance production in the reaction pi+- p ---> p pi+- pi+ pi- at 16-GeV/c, as obtained by a maximum likelihood fit

The Aachen-Berlin-Bonn-CERN-Heidelberg collaboration Honecker, R. ; Rumpf, K. ; Tsanos, N. ; et al.
Nucl.Phys.B 50 (1972) 157-165, 1972.
Inspire Record 84326 DOI 10.17182/hepdata.32751

Cross sections for resonance production in the reactions π ± p → p π ± π + π − at 16 GeV/ c are determined by a maximum likelihood fit, making use of the measurements of all individual events. The reactions are described by a simple parametrization based on an incoherent superposition of amplitudes for quasi two-body and quasi three-body processes and a non-resonant backgroud. In this way the reflections are accounted for in a consistent way. Thus cross sections are obtained for Δ ++ , Δ 0 , ρ 0 and f 0 production which do not suffer from the uncertainties of background subtraction typical of the usual technique of fitting individual mass distributions.

2 data tables

TWO PARTICLE RESONANCE CROSS SECTIONS.

CHANNEL FRACTIONS FROM THE FITS. THE AUTHORS WARN AGAINST DERIVING CROSS SECTIONS FOR THREE-PARTICLE RESONANCES.