Study of the reaction pi- p --> omega n at 3, 8, 6 and 8 GeV/c

Apel, W.D. ; Ausländer, J. ; Müller, H. ; et al.
Phys.Lett.B 55 (1975) 111-116, 1975.
Inspire Record 1388800 DOI 10.17182/hepdata.27881

Results are given for the production differential cross sections and the ω decay angular distribution in terms of the ω spin density matrix elements.

3 data tables

PAPER ALSO GIVES OFF-DIAGONAL ELEMENTS OF THE ERROR COVARIANCE MATRIX.

PAPER ALSO GIVES OFF-DIAGONAL ELEMENTS OF THE ERROR COVARIANCE MATRIX.

No description provided.


Study of the reaction $\pi^- p \rightarrow \omega^0 n$ at momenta 20 to 50 GeV/c

Bolotov, V.N. ; Isakov, V.V. ; Kakauridze, D.B. ; et al.
Phys.Lett.B 53 (1974) 217-220, 1974.
Inspire Record 1388799 DOI 10.17182/hepdata.27929

The mass spectrum of 3γ states produced in π−p collisions has been studied. A peak corresponding to ωo→πoγ decay in the π−p→ωon reaction was selected. The measurements were performed at the IHEP accelerator at momenta 21, 25, 32.5, 40 and 48 GeV/c. The reaction cross section decreases with the momentum in a power form (∼P−2.4) The differential cross section follows exponential t-dependence, exp (bt). The scattering cone shrinks slowly with the energy increase.

1 data table

No description provided.


Reaction $\pi^- p \to \omega n$ in the 15-{GeV}/$c$ - 40-{GeV}/$c$ Momentum Range

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Krüger, M. ; et al.
Lett.Nuovo Cim. 25 (1979) 493, 1979.
Inspire Record 142561 DOI 10.17182/hepdata.37383

None

7 data tables

DATA OBTAINED IN ASSUMPTION THAT RHO(MM=00,P=3,XYZ=SH)=1-2*RHO(MM=1-1,P=3,XYZ=SH).

INTEGRATED CROSS SECTION, INCLUDING SYSTEMATIC UNCERTAINTY IN ERRORS Axis error includes +- 15/15 contribution (DECAY-BR(BRN=OMEGA --> PI0 GAMMA,BR=0.088 +- 0.005)).

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Reaction $\pi^- p \to \eta^\prime n$ in the 15-{GeV}/$c$ - 40-{GeV}/$c$ Momentum Range

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Bertolucci, E. ; et al.
Phys.Lett.B 83 (1979) 131, 1979.
Inspire Record 141023 DOI 10.17182/hepdata.49657

Measurements were made of the cross section of the reactions π − p → ν ′(958)n, η ′ → 2 γ at momenta at 15, 20, 25, 30 and 40 GeV/c. The experiment was carried out on the IHEP 70 GeV accelerator using the 648 channel hodoscope spectrometer NICE for γ-ray detection. A total of 6000 η′ mesons were recorded. A sharp drop is seen in the differential cross section for t → 0. The dependences of the differential cross sections for the π − p → η ′n and π − p → η n on t are identical. On the basis of the ratio of the cross sections for these reactions at t = 0, i.e. R( η′ n ) t=0 = 0.55 ± 0.06 , the singlet-octet mixing angle for pseudoscalar mesons was determined to be β = −(18.2 ± 1.4)°.

8 data tables

AVERAGE RATIO IS 2.76 +- 0.07 PCT.

AVERAGE RATIO IS 0.52 +- 0.02.

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Study of narrow mesons near their thresholds

Binnie, D.M. ; Camilleri, L. ; Debenham, N.C. ; et al.
Phys.Rev.D 8 (1973) 2789-2813, 1973.
Inspire Record 93328 DOI 10.17182/hepdata.47579

A novel form of mass spectrometer has been used to measure the masses, widths, and cross sections of the η, ω, X0(958), and φ mesons near their respective thresholds in the reaction π−+p→missingmass+n. The incident momentum is varied in small steps through the threshold while neutrons of a given momentum are detected near zero degrees. The lower limit of the c.m. momentum P* at which measurements have been made ranges from about 50 MeV/c at the φ to about 30 MeV/c at the η. A somewhat low value for the ω mass, 782.3 ± 0.6 MeV, is found. The width of the X0 is < 1.9 MeV (95% confidence level). All four mesons show evidence of S-wave production, with values of σP* of 21.2 ± 1.8, 0.35 ± 0.03, and 0.29 ± 0.06 μb/(MeV/c) for the η, X0, and φ, respectively. A rapid rise in the ω cross section appears to be modified by a final-state interaction. The effect of this rise can probably be seen in some S11 pion-nucleon phase-shift solutions. Evidence is also presented of a sudden drop in the π+π− mass spectrum just above the threshold for the production of a K+K− pair. The paper includes a comprehensive discussion of the method and of the details of the spectrometer.

1 data table

CROSS SECTIONS NEAR THRESHOLD.


Study of omega Production Near Threshold in the Reaction pi- p --> omega n

Keyne, J. ; Binnie, D.M. ; Carr, J. ; et al.
Phys.Rev.D 14 (1976) 28-41, 1976.
Inspire Record 115718 DOI 10.17182/hepdata.24698

We have investigated ω production in the reaction π−p→ωn very close to threshold. The dependence of the mass, width, branching ratio, and cross section upon the final-state c.m. momentum, P*, were studied. The mass and width were independent of P* with values of 782.4 ± 0.5 and 10.22 ± 0.43 MeV, respectively. The branching ratio Γ(ω→π0γ)Γ(ω→π+π−π0) was also constant, having a value of 0.084 ± 0.013. An upper limit of 0.18 was set on the branching ratio Γ(ω→π0π0γ)Γ(ω→π0γ). We observed a rapid fall in the cross section below P*=100 MeV/c. This could not be explained in terms of S-wave production alone, but could be fitted by a resonant P wave plus a noninterfering S wave.

1 data table

CROSS SECTION DEPENDENCE ON FINAL STATE CENTRE OF MASS MOMENTUM. TABULATED VALUES TAKEN FROM TABLE 1 OF H. KARAMI ET AL., NP B154, 503 (1979).


ELASTIC SCATTERING AND OMEGA MESON PRODUCTION NEAR THE THRESHOLD OF PI- P ---> OMEGA N

Karami, H. ; Carr, J. ; Debenham, N.C. ; et al.
Nucl.Phys.B 154 (1979) 503-518, 1979.
Inspire Record 146573 DOI 10.17182/hepdata.34745

Measurements are reported of the differential cross section for the reaction π − +p→ ω +n from threshold to a final-state c.m. momentum P ∗ of 200 MeV /c . The previously reported fall in total cross section σ/P ∗ below about 100 MeV/ c is again seen. The differential cross section remains close to isotropic over the entire range. A paralle experiment on the variation in the elastic differential cross section across the threshold shows evidence of this threshold. The elastic data cover a range of incident moments from 1010 to 1180 MeV/ c in steps of 5 MeV/ c .

4 data tables

CROSS SECTION DEPENDENCE ON FINAL STATE CENTRE OF MASS MOMENTUM.

ANGULAR DISTRIBUTIONS ARE ALMOST ISOTROPIC.

LEGENDRE POLYNOMIAL COEFFICIENTS NORMALIZED SUCH THAT SIG = 4*PI*LEG(L=0).

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Baryon Exchange in 12-GeV/c pi- p Interactions

Arenton, M.W. ; Bacino, W.J. ; Hauptman, J.M. ; et al.
Nucl.Phys.B 141 (1978) 77-100, 1978.
Inspire Record 136191 DOI 10.17182/hepdata.34942

Final states produced by charged baryon exchange in π − p interactions at 12 GeV/ c laboratory momentum have been studied. Forward neutrons with momenta determined by a calorimeter to be greater than 8.5 ± 1.4 GeV/ c triggered the SLAC 40-inch hydrogen bubble chamber which operated at a 10 Hz expansion rate. We report data on the reactions π − p→n π − π + , π − p→n π − π + π 0 , and π − p→n π − π − π + π + . In π − n π − p→n π + , production of ϱ and f mesons is observed. Differential cross sections are derived and compared with data at lower incident momentum and with theoretical models. In π − p→n π − π + π 0 , ω production is observed with a differential cross section having a deep near u ′= 0.2 (GeV/ c ) 2 . In π − p→n π − π − π + π + , Δ − , ϱ and f production is observed . The observed mass distributions appear to indicate the production of wide resonaces decaying into ϱππ. Some evidence for ϱ-ω interference is also observed.

14 data tables

No description provided.

No description provided.

CORRECTED FOR BACKGROUND.

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Investigation of the reaction pi- p ---> omega0 n at 3.65, 4.50, and 5.50 gev/c

Holloway, L.E. ; Huld, B. ; Jordan, M. ; et al.
Phys.Rev.D 8 (1973) 2814-2826, 1973.
Inspire Record 93327 DOI 10.17182/hepdata.22060

An experiment using optical spark chambers and a neutron time-of-flight hodoscope has been performed at the Argonne National Laboratory on the reaction π−p→ω0n. The differential cross section and the experimentally accessible density-matrix elements were determined in the momentum transfer interval 0.05≤|t|≤1.0 (GeV/c)2 at each of three incident pion momenta 3.65, 4.50, and 5.50 GeV/c. Our results show the following general features: (1) a dip in the forward differential cross section for |t|≤0.2 (GeV/c)2, (2) a slope at larger momentum transfers which increases as the incident pion momentum increases, and (3) no dips in either dσdt or ρ11+ρ1−1, the natural-parity exchange combination, at |t|=0.6 (GeV/c)2.

2 data tables

No description provided.

No description provided.


A High Statistics Study of Omega0 Production

The Carleton-Michigan State-Ohio State-Toronto collaboration Shaevitz, M.H. ; Reay, N.W. ; Reibel, K. ; et al.
Phys.Rev.Lett. 36 (1976) 8, 1976.
Inspire Record 2932 DOI 10.17182/hepdata.37234

We report results from a study of π−p→ω0n at 6.0 GeV/c based on 28 000 events from a charged and neutral spectrometer. Background under the ω0 is only 7%, a large improvement over deuterium-bubble-chamber work. Density matrix elements, projected cross sections, and effective trajectories for natural and unnatural exchanges are presented.

4 data tables

No description provided.

No description provided.

No description provided.

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Study of the Reaction pi- p ---> Omega0 N at Momenta 20-GeV/c to 50-GeV/c

Bolotov, V.N. ; Isakov, V.V. ; Kakauridze, D.B. ; et al.
Sov.J.Nucl.Phys. 21 (1975) 166, 1975.
Inspire Record 91420 DOI 10.17182/hepdata.19115

None

2 data tables

No description provided.

AVERAGED OVER ALL MOMENTA OF EXPERIMENT. SLOPE = 6 +- 1 GEV**-2.


Omega Production in the Reaction pi- p --> pi+ pi- pi0 n at 8-GeV/c and 12-GeV/c

Dowell, J.D. ; Garvey, J. ; Jobes, M. ; et al.
Nucl.Phys.B 108 (1976) 30-44, 1976.
Inspire Record 100856 DOI 10.17182/hepdata.35781

The reaction π − p → ω n has been studied at 8 and 12 GeV / c incident momenta with the CERN Omega spectrometer using a neutron time of flight trigger. The differential cross sections and the ω-decay density matrix elements are presented as functions of the momentum transfer squared − t in the range of 0.02 to 0.80 GeV 2 . The data are used to evaluate the intercept and slope of both the natural and unnatural parity exchange trajectories. Regge exchange amplitude factorisation tests involving the reaction π N → ω N are investigated.

3 data tables

No description provided.

'FIT'.

'FIT'.


The Reaction pi- p --> omega N at Momenta from 20-GeV/c to 200-GeV/c

Dahl, O.I. ; Johnson, R.A. ; Kenney, R.W. ; et al.
Phys.Rev.Lett. 38 (1977) 54, 1977.
Inspire Record 110620 DOI 10.17182/hepdata.20987

The reaction π−p→ωn in the beam-momentum range from 20 to 200 GeV/c has been studied using data acquired at Fermilab. In this Letter, the integral and differential cross sections for this reaction are presented. The integral cross sections are considerably larger than those previously reported. The differential cross sections can be reproduced quite easily by Regge models. As predicted by such models, natural-parity exchange dominates production throughout this energy region.

3 data tables

D(SIG)/DT IS AVERAGE OVER T INTERVAL WITH NO FINITE-BIN-WIDTH CORRECTIONS.

No description provided.

REPRESENTATIVE SPIN DENSITY MATRIX ELEMENTS.