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Five-pion final state in p p annihilations at 0.70 to 1.1 GeV/c

Burns, R.R. ; Condon, P.E. ; Donahue, J. ; et al.
Nucl.Phys.B 85 (1975) 337-353, 1975.
Inspire Record 1392678 DOI 10.17182/hepdata.32116

Results are reported on the reaction p p → π + π + π − π − π 0 at six lab momenta spanning the region from 0.686 to 1.098 GeV/ c . The cross section for this process drops from 20.3 ± 1.2 mb at 0.686 GeV/ c to 13 1.0 mb at 1.098 GeV/ c . Resonance production is determined by means of a model which includes Bose symmetrization, Breit-Wigner amplitudes and Bose-Einstein correlations for the like-charged pion pairs in the nonresonant part of the amplitude. The likelihood fit to the resonance channels yields about 0.8% ηππ , 12% ϱ ± πππ , 2% f πππ , 8% ω ππ , 22% ϱ ± ϱ 0 π , 13% ωϱ 0 and 9% ω f with errors on the order of a few percent. Several percent A 1 ± ππ and X(1440) π were also needed to obtain good fits. The ϱ 0 πππ and ϱ 0 ϱ 0 π channels as well as A 2 ππ and A 1 0 ππ are consistent with zero. Reasonable fits to the mass distributions are obtained. Production angular distributions are found to be essentially uniform. The angular correlations between pion pairs are approximately fit by the simple model of resonance production with Bose symmetrization.

2 data tables
Table 1

Axis error includes +- 0.0/0.0 contribution.

Table 2

Axis error includes +- 0.0/0.0 contribution.


The Applicability of Zweig's Rule to anti-p p Annihilations at 3.6-GeV/c

Donald, R.A. ; Edwards, D.N. ; Houlden, M. ; et al.
Phys.Lett.B 61 (1976) 210-212, 1976.
Inspire Record 113109 DOI 10.17182/hepdata.27692

The final states øππ and øKK̄ arising from p̄p annihilations at 3.6 GeV/ c have been studied. The results are in agreement with Zweig's rule contrary to what is observed in high energy pp collisions.

1 data table
Table 1

No description provided.


New data on OZI rule violation in anti-p p annihilation at rest.

The OBELIX collaboration Bertin, A. ; Bruschi, M. ; De Castro, S. ; et al.
Phys.Lett.B 388 (1996) 450-456, 1996.
Inspire Record 420512 DOI 10.17182/hepdata.41681

The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+ pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decreasing of the dipion mass, which demonstrates the difference in the phi and omega production mechanisms. An indication on the momentum transfer dependence of the apparent OZI rule violation for phi production from the 3S1 initial state was found.

1 data table
Table 1

(C=CORRECTED) the ratio with phase space correctio. The annihilation in liquid hydrogen (C=LIQUID) and in hydrogen at 3 atm (C=P).


The annihilation process p anti-p ---> 2pi+ 2pi- pi0 at 2.5 gev/c

Clayton, J. ; Mason, P. ; Muirhead, H. ; et al.
Nucl.Phys.B 30 (1971) 605-616, 1971.
Inspire Record 68592 DOI 10.17182/hepdata.33476

Substantial production of the resonances ϱ, f and ω has been observed in this reaction. In contrast with the channel p p → 2π + 2π − , associated production of resonances was found to occur. The behaviour of the associated production of ω-mesons with other resonances is shown to be consistent with some very simple assumptions. Alternative methods of displaying data for p p → ππω are discussed; it is shown that the longitudinal phase plot for this reaction is unlike that obtained for any previously reported reaction. Reasonable agreement for the behaviour of this channel is found with the multiperipheral model of Chan, Łoskiewicz and Allison.

2 data tables
Table 1

STATISTICAL ERRORS ONLY. FOR MULTIPLE PI0 PRODUCTION, RESULTS ARE MODEL DEPENDENT.

Table 2

ANALYSIS OF 5PION FINAL STATE. DISTRIBUTION FITTED WITH FIXED MASS AND WIDTH RESONANCES, THEN ONLY EVENTS ABOVE (FITTED) BACKGROUND TAKEN. CROSS SECTIONS CALCULATED BY PDG (COMPILATION PDG3).


Anti-p p Annihilations Into Four and Five Pion Final States in the t (2190) Region

Handler, T. ; Jacques, P. ; Jones, M. ; et al.
Nucl.Phys.B 101 (1975) 35, 1975.
Inspire Record 99552 DOI 10.17182/hepdata.36053

New data from a 600 000 picture exposure of the BNL 31 inch hydrogen bubble chamber to a separated antiproton beam have been analyzed to try to determine if the π + π − π + π − or π + π − π + π − π 0 final states contribute any broad or narrow structure in the T(2190) region. The resonance channel fractions determined by maximum likelihood fits are all consistent with smooth behavior through the T-region and therefore there is no significant evidence that any of these resonance channels contributes to the broad bump in the total cross section. The errors on some of the fractions, however, limit the sensitivity to ∼ 0.5 mb for enhancements in these channels.

2 data tables
Table 1

RESONANCE CHANNEL PERCENTAGES FROM FIT TO PI+ PI- PI+ PI- FINAL STATE.

Table 2

RESONANCE CHANNEL PERCENTAGES FROM FIT TO PI+ PI- PI+ PI- PI0 FINAL STATE.


Phi and omega Meson Production in anti-p p Annihilations at 0.7-GeV/c-0.76-GeV/c and the OZI Rule

The BOMBAY-CERN-COLLEGE DE FRANCE-MADRID collaboration Cooper-Sarkar, Amanda M. ; Ganguli, S.N. ; Malhotra, P.K. ; et al.
Nucl.Phys.B 146 (1978) 1-10, 1978.
Inspire Record 137031 DOI 10.17182/hepdata.34858

The production of the φ and ω mesons has been studied in the reactions p p → φ(ω)π + π − and p p → φ(ω) ϱ 0 at 0.70–0.76 GeV /c . The c.m. angular distribution of the φ meson in the reaction p p → φπ + π − is found to be consistent with isotropy. The corresponding distribution for ω is not. the ratio σ( p p → φπ + π − ) σ( p p → ωπ + π − ) is (10 ± 2.4) · 10 −3 , which leads to a value of (19 ± 5) · 10 −3 when corrected for the phase-space factor. Implications of this result for the OZI rule are discussed.

2 data tables
Table 1

No description provided.

Table 2

No description provided.