Date

Search for structure in pi- p ---> lambda k0 at sigma k threshold

Nelson, B. ; Knasel, T.M. ; Lindquist, J. ; et al.
Phys.Rev.Lett. 31 (1973) 901-904, 1973.
Inspire Record 83771 DOI 10.17182/hepdata.21338

We have measured the cross section, the angular distribution, and the Λ polarization for the reaction π−p→ΛK0. A spark-chamber spectrometer was used to collect 8400 ΛK0 events at fourteen beam momenta near ΣK threshold. Our data do not show the prominent cross-section enhancement suggested by some previous experiments. However, detailed structure in the cross section and the angular distribution agrees well with a simple model which includes a cusp effect at ΣK threshold.

3 data tables

No description provided.

BACKWARD-FORWARD PRODUCTION ASYMMETRY.

AVERAGE LAMBDA POLARIZATION.


Recoil-proton polarization in neutral-pion photoproduction and in proton Compton scattering

Deutsch, M. ; Golub, L. ; Kijewski, P. ; et al.
Phys.Rev.Lett. 29 (1972) 1752-1755, 1972.
Inspire Record 84562 DOI 10.17182/hepdata.21426

We have measured the polarization of the recoil proton in the reactions γp→π0p and γp→γp for incident photon energies between 3 and 7 GeV, and t values from -0.2 to -0.65 GeV2. The polarization in neutral-pion production varies from 0 to -1 over this range. Contrary to expectation, it does not agree completely with the polarized-target asymmetry.

1 data table

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Sigma+ polarization in pi+ n ---> k0 sigma+ from 1.1 to 2.4 gev/c

Davies, D.W. ; Abolins, M.A. ; Dahl, O.I. ; et al.
Phys.Rev.D 7 (1973) 3546-3548, 1973.
Inspire Record 82052 DOI 10.17182/hepdata.22133

We observe an energy-dependent polarization of the Σ+ produced in the reaction π+n→K0Σ+ at incident beam momenta between 1.1 and 2.4 GeV/c. These data form a significant source of information on the Σ− polarization in the charge-symmetric reaction π−p→K+Σ−.

2 data tables

INTEGRATED OVER ALL PRODUCTION ANGLES.

No description provided.


Measurements of the polarization in proton proton elastic scattering from 2.50 to 5.15 gev/c

Parry, J.H. ; Booth, N.E. ; Conforto, G. ; et al.
Phys.Rev.D 8 (1973) 45-63, 1973.
Inspire Record 81983 DOI 10.17182/hepdata.22058

In an experiment at the Argonne Zero-Gradient Synchrotron we have measured values of the polarization parameter P(t) in the elastic scattering of negative pions, positive pions, positive kaons, and protons on protons at several incident laboratory momenta from 2.50 to 5.15 GeVc, and for values of the momentum transfer variable −t from 0.2 to 2.0 (GeVc)2. The final results from p−p elastic scattering presented here extend our knowledge of the polarization to much larger values of −t than the results of previous measurements. Outstanding features revealed by these polarization data include (1) the development of a dip at about −t=0.7 (GeVc)2, with (2) a substantial secondary peak at larger values of −t and (3) the gradual diminution of the maximum polarization with increasing energy. It is possible to fit the t dependence of the experimental results with a simple model. The energy dependence of the polarized cross sections is also discussed.

7 data tables

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Vector Meson Production by Polarized Photons at 2.8-GeV, 4.7-GeV, and 9.3-GeV

Ballam, Joseph ; Chadwick, G.B. ; Eisenberg, Y. ; et al.
Phys.Rev.D 7 (1973) 3150, 1973.
Inspire Record 73602 DOI 10.17182/hepdata.43496

We present results on vector-meson photoproduction via γp→Vp in the LBL-SLAC 82-in. hydrogen bubble chamber exposed to a linearly polarized photon beam at 2.8, 4.7, and 9.3 GeV. We find ρ0 production to have the characteristics of a diffractive process, i.e., a cross section decreasing slowly with energy and a differential cross section with slope of ∼ 6.5 GeV−2. Within errors the ρ0 production amplitudes are entirely due to natural-parity exchange. s-channel helicity is conserved to a high degree in the γ→ρ0 transition. We find evidence for small helicity-flip amplitudes for ππ pairs in the ρ0 region. Photoproduction of ω mesons is separated into its natural- (σN) and unnatural- (σU) parity-exchange contributions. The Eγ and t dependence and the spin density matrix of the unnatural-parity-exchange contribution are consistent with a one-pion-exchange process. The natural-parity-exchange part has characteristics similar to ρ0 production. At 9.3 GeV the ratio of σ(ρ0) to σN(ω) is ∼ 7. The slope of the φ differential cross section is ∼ 4.5 GeV−2, smaller than that of ρ0 and ω production. Natural-parity exchange is the main contributor to φ production. No evidence for higher-mass vector mesons is found in ππ, πππ, or KK¯ final states. The s and t dependences of Compton scattering as calculated from ρ, ω, and φ photoproduction using vector-meson dominance agree with experiment, but the predicted Compton cross section is too small by a factor of 2.

47 data tables

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0- 1/2+ final states in k- p interactions at 3.95 gev/c

Moscoso, L. ; Hubbard, J.R. ; Leveque, A. ; et al.
Nucl.Phys.B 36 (1972) 332-344, 1972.
Inspire Record 75362 DOI 10.17182/hepdata.33015

Final states π − Σ + , π + Σ − , π o Λ and ηΛ were studied for K − p reactions at 3.95 GeV/ c . Cross sections, angular distributions and polarizations are presented. Data for π − Σ + and π o Λ production are compared to the line-reversed πp reactions at the same beam momentum. Baryon-exchange peaks are presented for the Σ + π − , Σ − π + and Λπ o final states.

10 data tables

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Measurements of spin rotation parameters in pion-nucleon elastic scattering at 6 gev/c and at 16 gev/c

De Lesquen, A. ; Amblard, B. ; Beurtey, R. ; et al.
Phys.Lett.B 40 (1972) 277-280, 1972.
Inspire Record 75722 DOI 10.17182/hepdata.28284

The spin rotation parameter R has been measured at CERN, for π ± p at 6 GeV c and for π − p at 16 GeV c , with t ranging from −0.19 to −0.51 ( GeV c ) 2 . The parameter A was measured for π − p at 6 GeV c in the interval between t =−0.19 and minus;0.41 ( GeV c ) 2 . The averaged values are the following; R (+6) =−0.08±0.04, R (−6) =−0.23±0.05 and R (−16) =−0.23±0.05. The values obtained for A are close to +1.

4 data tables

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Polarisation in the reaction pi+ p ---> k+ sigma+ at 1.11 gev/c

Bellamy, E.H. ; Anderson, J. ; Crawford, J.F. ; et al.
Phys.Lett.B 39 (1972) 299-302, 1972.
Inspire Record 75797 DOI 10.17182/hepdata.28308

The polarisation of the recoil sigma in the reaction π + p → K + Σ + has been measured at 12 production angles at a beam momentum of 1.11 GeV /c using counters and spark chambers. The new data are compared with existing phase shift solutions of π p → K Σ channels in the low energy region.

1 data table

THE ASYMMETRY PARAMETER, ALPHA, FOR SIGMA+ --> P PI0 IS CLOSE TO -1. THE LAST DATA VALUE IS DEDUCED FROM ALL THE EXPERIMENTAL EVENTS.


Pi+- and pi0 production by polarized photons in the resonance region

Alspector, J. ; Fox, D. ; Luckey, David ; et al.
Phys.Rev.Lett. 28 (1972) 1403-1406, 1972.
Inspire Record 75484 DOI 10.17182/hepdata.21872

We have measured the cross sections at 90° c.m. for π± and π0 photoproduction with polarized photons. The photon energies ranged from 0.8 to 2.2 GeV. We compare the resonant "bumps" in the cross section with theoretical models. The measured asymmetry agrees with a quark-model calculation though the predicted cross sections are low.

5 data tables

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Proton-deuteron elastic scattering at 1.0 gev/c

Booth, N.E. ; Dolnick, C. ; Esterling, R.J. ; et al.
Phys.Rev.D 4 (1971) 1261-1267, 1971.
Inspire Record 74877 DOI 10.17182/hepdata.23150

The differential cross section and polarization in p−d elastic scattering have been measured at an incident laboratory momentum of 0.99 GeVc (kinetic energy 425 MeV) over most of the angular range. Elastic p−d scattering events from a CD2 target were selected by angular correlation, coplanarity, and time of flight. A significant feature of the results is the large positive polarization at backward scattering angles.

1 data table

No description provided.