Results from a high-statistics experiment involving an exposure of the SLAC 82-in. hydrogen bubble chamber to a beam of 8-GeV/c π− yielding a final state of π−π+π−p are presented. Copious production of ρ, Δ++, and f is found. Considerable quasi-two-body production in which one particle decays to one of the above resonances is also observed. Some double-resonance production involving baryon and meson resonances is also seen. The production properties of ρ, Δ++, and f mesons are well described by a double-Regge model.
TOPOLOGICAL CROSS SECTIONS. FIRST 2 PRONG VALUE CONTAINS ELASTIC. 0PRONG IS TAKEN FROM A SMALLER AND DIFFERENT PARTIAL SAMPLE.
CROSS SECTION CALCULATED VIA THE OPTICAL THEOREM AS A CROSS CHECK.
SPECIFIC CHANNEL CROSS SECTIONS.
A quasi-two-body model based on one-particle exchange and diffraction dissociation has been fitted to data from π−p interactions at 3.9 and 11.9 GeV/c in which a nucleon and 3-6 pions are present in the final state. It is used to estimate partial cross sections for the contributing interaction mechanisms and the dominant resonances which are produced at these energies. The energy dependence of the cross sections is examined and found to be consistent with expected behavior, and reactions are compared and found to agree with simple factorization.
No description provided.
No description provided.
No description provided.
Fourteen reaction channels contributing to the final state have been separated by a prism-plot analysis of π−p→π−π−π+p interactions at 13.2 GeV/c. The results of this study are presented in terms of partial and differential cross sections, invariant-mass and decay-angular distributions, and comparisons with other separation techniques for the various resonant states.
No description provided.
No description provided.
We have analyzed backward meson production in the reaction π − p → p f π + π − π − at 9 GeV/ c and 12 GeV/ c incident π − momenta, from an experiment performed at the CERN Ω Spectrometer using a fast proton (p f ) trigger device. We find strong production of quasi-two-body processes N ∗ ϱ and N ∗ f with a production mechanism consistent with u -channel nucleon exchange. At a lower level, we observe N ∗ π processes with a 3-body baryon decay through Δ(1232)π. In the (3π) − system, we find evidence for A 1 − and clear A 2 − backward production with similar cross sections (≈0.5 μb).
No description provided.
U-HELICITY JACKSON FRAME.
U-HELICITY JACKSON FRAME.
A multidimensional analysis of the reaction π − p → π − p π + π − at 3.93 GeV/ c is presented. Its results are compared to those obtained with conventional methods and its limitations are discussed.
No description provided.
We have studied backward baryon and meson production in π−p→pπ+π−π− at 8.0 GeV/c using a streamer chamber triggered by the detection of a fast forward proton. Our data sample (1227 events) displays prominent N*ρ and N*f quasi-two-body production. These states are investigated with regard to the peripheral nature of the production mechanism and sequential decay of the excited baryon and meson systems. The quasi-two-body production of N*ρ and N*f intermediate states is consistent with u-channel proton exchange as the dominant production mechanism. In the π+π−π− mass distribution we observe a 3- to 4- standard-deviation enhancement at M3π=1897±17 MeV/c2 with full width at half maximum = 110 ± 82 MeV/c2, but find no but find no evidence for backward A1 or A2 production. We observe Δ++(1232) production in the pπ+ effective mass distribution.
THESE VALUES ASSUME ONLY RHO(11) IS NON-ZERO. VALUES FOR OTHER RHO(MM) ARE QUOTED IN PAPER. SIG ERRORS INCLUDE OVER-ALL NORMALIZATION UNCERTAINTY, BUT NO BACKGROUND CORRECTIONS HAVE BEEN MADE.
STATISTICAL ERRORS ONLY, NO BACKGROUND CORRECTION.
STATISTICAL ERRORS ONLY, NO BACKGROUND CORRECTION.
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