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PHOTOPRODUCTION OF CHARGED PIONS FROM DEUTERIUM AT GAMMA ENERGIES FROM 900-MEV TO 1800-MEV AND PION ANGLES BETWEEN 65-DEGREES AND 125-DEGREES

Besch, H.j. ; Krautschneider, F. ; Sternemann, K.p. ; et al.

Z.Phys.C 16 (1982) 1-6, 1982.

Inspire Record 184969 DOI 10.17182/hepdata.16386

π−-photoproduction cross sections from neutrons have been measured with a deuterium target at effective γ-energies from 900 to 1,800 MeV and pion centre-of-mass angles 65 to 125°. The outgoing pion and proton were detected in coincidence, the pion with a magnetic spectrometer and the proton with a time-of-flight system. To test the reliability of the analysis method, a comparison of π+-photoproduction from protons and deuterons was made with a slightly modified apparatus. It was found adequate to use the spectator model with a Huthèn wave function.

1 data table

Table 1

No description provided.

Measurement of Differential Cross-Sections for Radiative Pion-Proton Capture in the Second Resonance Region

Weiss, A.J. ; Blasberg, D.J. ; Comiso, J.C. ; et al.

Nucl.Phys.B 101 (1975) 1-18, 1975.

Inspire Record 2234 DOI 10.17182/hepdata.36075

Differential cross-section measurements for π − p → γ n, consisting of three angular distributions at 618, 676 and 718 MeV/ c , and the energy dependence at θ γ = 90° for seven incident pion momenta between 502 and 888 MeV/ c , are presented. Our data qualitatively support recent multipole analyses. Agreement with the Scheffler et al. results for the inverse reaction, γ n → π − p, using a ( π − -recoil p) coincidence technique is good excluding a large violation of time reversal invariance. The agreement with γ n → π − p data obtained using the R ( π − / π + ) ratio technique or a deuterium bubble chamber is only qualitative.

7 data tables

Table 1

Axis error includes +- 6.6/6.6 contribution.

Table 2

Axis error includes +- 6.2/6.2 contribution.

Table 3

Axis error includes +- 6.0/6.0 contribution.

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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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Inverse Pion Photoproduction in the Vicinity of the p33 (1232) Resonance and a Test of Time Reversal Invariance

Comiso, J.C. ; Blasberg, D.J. ; Haddock, R.P. ; et al.

Phys.Rev.D 12 (1975) 719, 1975.

Inspire Record 91072 DOI 10.17182/hepdata.24803

Differential cross-section measurements are presented for π−p→γn at five energies around the p33(1232) resonance. A detailed comparison is made with γn→π−p deduced from γd experiments. In general, the results are in support of detailed balance. Using the Christ-Lee-Donnachie-Shaw model, our new data indicate that the T-violating phase in the isovector part of the M1+ multipole is less than 2°, which is a very sensitive test of time-reversal invariance. No evidence is found for a possible isotensor component of the electromagnetic current. Our data are compared to various multipole analyses. In general, the agreement is poor.

11 data tables

Table 1

Axis error includes +- 6.3/6.3 contribution.

Table 2

No description provided.

Table 3

No description provided.

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Differential Cross-Sections for pi- p --> gamma n in the First Resonance Region

Guex, L.H. ; Joseph, C. ; Tran, M.T. ; et al.

Phys.Lett.B 55 (1975) 101-106, 1975.

Inspire Record 90715 DOI 10.17182/hepdata.27879

Differential cross-sections for negative pion radiative capture on protons at c.m. angles of 60°, 90°, and 120° have been measured at nine incident laboratory energies between 110 and 270 MeV. Comparison with measured cross-sections for pion photoproduction and with conventional multipole analyses shows neither evidence for a violation of time reversal invariance nor for an isotensor component of the electromagnetic current of hardrons.

7 data tables

Table 1

Axis error includes +- 0.0/0.0 contribution (QUOTED ERRORS INCLUDE THE 5 PCT AND 3 PCT UNCERTAINTIES IN THE NEUTRON AND PHOTON DETECTOR EFFICIENCIES).

Table 2

Axis error includes +- 0.0/0.0 contribution (QUOTED ERRORS INCLUDE THE 5 PCT AND 3 PCT UNCERTAINTIES IN THE NEUTRON AND PHOTON DETECTOR EFFICIENCIES).

Table 3

Axis error includes +- 0.0/0.0 contribution (QUOTED ERRORS INCLUDE THE 5 PCT AND 3 PCT UNCERTAINTIES IN THE NEUTRON AND PHOTON DETECTOR EFFICIENCIES).