McCracken, M.E.
Photoproduction
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Rho+- Photoproduction at 9.6-GeV

Abramson, J. ; Andrews, D.E. ; Busnello, R. ; et al.
Phys.Rev.Lett. 36 (1976) 1432, 1976.
Inspire Record 108497 DOI 10.17182/hepdata.21105

ρ± photoproduction from hydrogen and deuterium at 9.6 GeV is studied. The reactions γp→ρ+n and γp→ρ−Δ++(1236) have cross sections much larger than expected from pion exchange alone. t distributions do not show the sharp forward peak characteristic of one-pion exchange contributions. Density matrices indicate an isotropic decay distribution. The ratio of ρ+ to ρ− production on deuterium differs from unity and by the amount expected from interference between ρ and A2 exchanges. We conclude that π exchange is unimportant for ρ± photoproduction, and infer that ρ exchange dominates.

7 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

DENSITY MATRICES IN HELICITY FRAME - UNPUBLISHED.

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An Improved Upper Limit for Photoproduction of psi (3105) Near Threshold

Andrews, D.E. ; Harvey, John R. ; Lobkowicz, F. ; et al.
Phys.Rev.Lett. 34 (1975) 1134-1136, 1975.
Inspire Record 98255 DOI 10.17182/hepdata.21225

An improved upper limit for ψ photoproduction near threshold is presented.

1 data table
Table 1

The branching ratio for J/PSI --> E+ E- is taken as 0.06.


Search for photoproduction of psi(3105)

Andrews, D.E. ; Harvey, J. ; Lobkowicz, F. ; et al.
Phys.Rev.Lett. 34 (1975) 231-233, 1975.
Inspire Record 106690 DOI 10.17182/hepdata.60290

The product of the photoproduction cross section at 11.1 GeV for ψ(3105) on nucleons times the branching ratio for ψ into e+e− is less than 75 pb, at the 90% confidence level. This result implies a ψ-nucleon total cross section of less than 1.2 mb.

1 data table
Table 1

The branching ratio for J/PSI --> E+ E- is taken as 0.06.


Differential cross-sections of pi- p ---> gamma n for 317, 452, and 491 mev/c incident pion momentum

Berardo, P.A. ; Haddock, R.P. ; Nefkens, B.M.K. ; et al.
Phys.Rev.D 9 (1974) 621-643, 1974.
Inspire Record 93116 DOI 10.17182/hepdata.21950

The differential cross sections of π−p→γn at center-of-mass energy Ẽ=1363, 1337, and 1245 MeV are presented. The angular distributions are compared with recent γn→π−p experiments. Though the cross sections for π−p→γn are somewhat lower than those for the inverse reaction, when all uncertainties are considered, we find that our data are in acceptable agreement at all three energies with the inverse reaction determined from π−π+ ratio measurements, in support of time-reversal invariance. The agreement with bubble-chamber measurements at Ẽ=1363 and 1337 MeV is less satisfactory. The isotensor dip test applied to our data is inconclusive. Our measurements are compared with many multipole analyses, disagreeing with most, in particular with pure fixed- t dispersion relation calculations. We find no evidence, in the sense suggested by Donnachie, for the classification of the P11(1470) resonance in an SU(3) antidecuplet. The data are consistent with a small radiative decay of the P11(1470) resonance, as predicted by quark models.

6 data tables
Table 1

Axis error includes +- 6/6 contribution.

Table 2

Axis error includes +- 4.5/4.5 contribution.

Table 3

Axis error includes +- 4.2/4.2 contribution.

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Positive-pion photoproduction in the backward direction

Ekstrand, K. ; Browman, A. ; Hand, L. ; et al.
Phys.Rev.D 6 (1972) 1-11, 1972.
Inspire Record 74041 DOI 10.17182/hepdata.3606

The reaction γ+p→π++n has been measured for incident γ-ray energies from 0.7 to 8 GeV and recoil lab angles from 170° to 180° using the Cornell 10-GeV synchrotron. The data presented here cover the transition region between the resonance region and the high-energy region studied at SLAC. The results are compared with various phenomenological Regge-pole analyses and with similar data on π0 photoproduction taken at DESY.

2 data tables
Table 1

No description provided.

Table 2

No description provided.