Date

Pi- production with linearly polarized photons at 3.4 gev

Burfeindt, H. ; Buschhorn, G. ; Geweniger, C. ; et al.
Nucl.Phys.B 59 (1973) 87-92, 1973.
Inspire Record 83969 DOI 10.17182/hepdata.8010

The asymmetry of the reaction γ d π − p ( p S ) with linearly polarized photons has been measured at 3.4 GeV and momentum transfers √− t between 0.2 and 0.8 GeV/ c . As in π + production, the asymmetry is large and positive at small momentum transfers but drops rapidly with increasing √− t , crossing zero around √− t = 0.55 GeV/ c .

2 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

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Polarization in backward elastic pi+ p scattering at 2.0, 3.5 and 4.0 gev/c

Bradamante, F. ; Conetti, S. ; Daum, C. ; et al.
Nucl.Phys.B 56 (1973) 356-380, 1973.
Inspire Record 84069 DOI 10.17182/hepdata.6773

Data on polarization in backward elastic π + p scattering at 2.0, 3.5 and 4.0 GeV/ c are presented. The data at 2.0 GeV/ c are compared with the result of a recent phase-shift analysis. Our data at 3.5 and 4.0 GeV/ c , and existing data above 3 GeV/ c , show no significant energy dependence of the polarization over the measured u -range. A comparison with Regge models and with results from amplitude analysis is made.

6 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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Study of the reactions pi+ p ---> k+ sigma+ and pi+ p ---> k+ y*+(1385) between 3.5 and 14 gev/c

Bashian, A. ; Finocchiaro, G. ; Good, M.L. ; et al.
Phys.Rev.D 4 (1971) 2667-2679, 1971.
Inspire Record 74763 DOI 10.17182/hepdata.23097

Measurements of the differential cross section for the reactions π+p→K+Σ+ and π+p→K+Y*+(1385) are reported at 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0, 6.0, 10.0, and 14.0 GeV/c. Polarization in π+p→K+Σ+ is also reported at 6.0, 10.0, and 14.0 GeV/c. At small |t|, the cross section for π+p→K+Σ+ is well described by an exponential Aebt with slopes in the range b≈8−10 (GeV/c)−2; for |t|>0.5 (GeV/c)2 this slope decreases considerably. The cross section for π+p→K+Y*+(1385) is well described for |t|>0.2 (GeV/c)2 by a single exponential of slope about half that for π+p→K+Σ+; there is no break near |t|>0.5 (GeV/c)2. We observe a dip in this cross section near t=0. The polarization in π+p→K+Σ+ is consistent with zero for |t|<0.4 (GeV/c)2 and becomes large and positive for larger |t|.

22 data tables

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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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Recoil polarization in K$^+ \Lambda$ photoproduction at 5 gev

Vogel, G. ; Burfeindt, H. ; Buschhorn, G. ; et al.
Phys.Lett.B 40 (1972) 513-516, 1972.
Inspire Record 75679 DOI 10.17182/hepdata.28291

The Λ polarization in the reaction γp → K + Λ has been measured using the decay Λ → pπ − as an analyzer. It is found to be large and negative in the momentum transer range 0.2 ⩽ | t | ⩽ 1.0 (GeV/ c ) 2 .

1 data table

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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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Measurement of the polarization parameter in backward pi+ p elastic scattering at 1.60, 1.80, 2.11, and 2.31 gev/c

Burleson, G. ; Hill, D. ; Kato, S. ; et al.
Phys.Rev.Lett. 26 (1971) 338-340, 1971.
Inspire Record 69051 DOI 10.17182/hepdata.21558

Measurements of polarization in π+p elastic scattering have been made at 1.60, 1.80, 2.11, and 2.31 GeVc. The data cover the entire angular range, with emphasis on the backward region. Comparisons have been made with both u-channel and t-channel models, as well as with predictions of phase-shift analyses. While the agreement is generally poor in all cases, the best agreement is with some t-channel predictions.

4 data tables

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Measurements of polarization in pi- p elastic scattering at large angles

Hill, D. ; Koehler, P.F.M. ; Novey, T.B. ; et al.
Phys.Rev.Lett. 27 (1971) 1241-1243, 1971.
Inspire Record 68894 DOI 10.17182/hepdata.229

We have made measurements of polarization in π−p elastic scattering, with emphasis over the backward region, at 1.60 to 2.28 GeVc. The results indicate the absence of u-channel dominance in the backward region, as was observed in the case of π+p scattering. Comparisons have been made with predictions of various phase-shift analyses which show that the agreement is generally very poor in the backward region.

9 data tables

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Measurement of the polarization parameter in pi+ p elastic scattering at 10, 14 and 17.5 gev/c and for /t/ >=2(gev/c)-squared

Borghini, M. ; Dick, L. ; Olivier, J.C. ; et al.
Phys.Lett.B 36 (1971) 493-496, 1971.
Inspire Record 69147 DOI 10.17182/hepdata.37236

Results on polarization in π − p and π + p forward elastic scattering at 10, 14 and 17.5 GeV/ c are presented.

5 data tables

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