Photoproduction of charged pions near threshold

Adamovich, M.I. ; Gorzhevskaya, É.G. ; Larionova, V.G. ; et al.
Sov.Phys.JETP 11 (1960) 779-782, 1960.
Inspire Record 1392962 DOI 10.17182/hepdata.71292

None

12 data tables

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Total cross-section measurement of $\pi^{-}$ photoproduction on deuteron in the first-resonance region.

Chiefari, G. ; Drago, E. ; Napolitano, M. ; et al.
Lett.Nuovo Cim. 13 (1975) 129-133, 1975.
Inspire Record 1393351 DOI 10.17182/hepdata.37447

None

2 data tables

No description provided.

CROSS SECTION ON NEUTRON CALCULATED FROM DEUTERIUM MEASUREMENTS USING THE NUCLEON SPECTATOR MODEL.


SINGLE NEGATIVE PION PHOTOPRODUCTION ON DEUTERIUM IN THE ENERGY RANGE (500-MeV - 800-MeV): PRELIMINARY INVESTIGATION

Beneventano, M. ; de Notaristefani, F. ; Monacelli, P. ; et al.
Lett.Nuovo Cim. 1 (1969) 113-118, 1969.
Inspire Record 1098439 DOI 10.17182/hepdata.37462

None

1 data table

No description provided.


Pion production with polarized photons and test of vector dominance model

Geweniger, Chr. ; Heide, P. ; Kötz, U. ; et al.
Phys.Lett.B 28 (1968) 155-156, 1968.
Inspire Record 1392676 DOI 10.17182/hepdata.29098

Cross section asymmetries for the sum of single π + and π - production with polarized photons of 3.4 GeV have been measured. The results disagree with calculations based on the vector dominance model using experimental data of vector meson production in π beams.

1 data table

No description provided.


Determination of the γ - π - ρ coupling constant from the −/+ ratio for photoproduction from deuterium

Pine, J. ; Bazin, M. ;
Phys.Lett. 5 (1963) 168-170, 1963.
Inspire Record 1388798 DOI 10.17182/hepdata.27961

None

3 data tables

No description provided.

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Negative pion photoproduction off neutron at 180$sup 0$ in the energy range between 300 and 1200 MeV

Takasaki, F. ;
INSJ-126, 1971.
Inspire Record 1085257 DOI 10.17182/hepdata.40522

None

50 data tables

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Beam asymmetry $\Sigma$ measurements on the $\pi^-$ photoproduction off neutrons

The Graal collaboration Mandaglio, G. ; Mammoliti, F. ; Manganaro, M. ; et al.
Phys.Rev.C 82 (2010) 045209, 2010.
Inspire Record 872319 DOI 10.17182/hepdata.63833

The $\Sigma$ beam asymmetry in the photoproduction of negative pions from quasi-free neutrons in a deuterium target was measured at Graal in the energy interval 700 - 1500 MeV and a wide angular range, using polarized and tagged photons. The results are compared with recent partial wave analyses.

11 data tables

The measured beam polarization asymmetry for photon energy 753 MeV.

The measured beam polarization asymmetry for photon energy 820 MeV.

The measured beam polarization asymmetry for photon energy 884 MeV.

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Cross section measurements of charged pion photoproduction in hydrogen and deuterium from 1.1-GeV to 5.5-GeV.

The Jefferson Lab Hall A & Jefferson Lab E94-104 collaborations Zhu, L.Y. ; Arrington, J. ; Averett, T. ; et al.
Phys.Rev.C 71 (2005) 044603, 2005.
Inspire Record 659852 DOI 10.17182/hepdata.31680

The differential cross section for the gamma +n --> pi- + p and the gamma + p --> pi+ n processes were measured at Jefferson Lab. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to center-of-mass energies from 1.7 to 3.4 GeV. The pion center-of-mass angles varied from 50 degree to 110 degree. The pi- and pi+ photoproduction data both exhibit a global scaling behavior at high energies and high transverse momenta, consistent with the constituent counting rule prediction and the existing pi+ data. The data suggest possible substructure of the scaling behavior, which might be oscillations around the scaling value. The data show an enhancement in the scaled cross section at center-of-mass energy near 2.2 GeV. The differential cross section ratios at high energies and high transverse momenta can be described by calculations based on one-hard-gluon-exchange diagrams.

14 data tables

Differential cross section for the process GAMMA N --> PI- P for an incident electron energy of 5.614 GeV.

Differential cross section for the process GAMMA N --> PI- P for an incident electron energy of 4.236 GeV.

Differential cross section for the process GAMMA N --> PI- P for an incident electron energy of 3.400 GeV.

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DIFFERENTIAL CROSS-SECTION FOR PI- P ---> GAMMA N FROM 427-MEV/C TO 625-MEV/C

Kim, G.J. ; Arends, J. ; Briscoe, W.J. ; et al.
Phys.Rev.D 40 (1989) 244-247, 1989.
Inspire Record 285141 DOI 10.17182/hepdata.23110

Differential cross sections for π−p→γn have been determined from 427 to 625 MeV/c, mainly at 90° and 110° c.m. The data were obtained by combining measurements of the Panofsky ratio in flight with known charge-exchange cross sections. The results are compared with γn→π−p data derived from γd experiments; the difference is typically 30%. The radiative decay amplitudes of neutral πN resonances are therefore uncertain by at least 30%.

3 data tables

Charge exchange cross section from PWA.

PI- P --> GAMMA N cross section.

GAMMA N --> PI- P cross section calculated using detailed balance.


Analysis of the reaction gamma n ---> p pi- in the first and second resonance regions

Rossi, V. ; Piazza, A. ; Susinno, G. ; et al.
Nuovo Cim.A 13 (1973) 59-89, 1973.
Inspire Record 87242 DOI 10.17182/hepdata.37785

The final results of an experimental investigation of the reaction γ+n→p+π− performed with a deuterium bubble chamber at the 1 GeV Frascati electrosynchrotron are presented. Total and differential cross-sections on neutrons are extracted by means of the spectator model, the reliability of which has been checked by numerous tests and is extensively discussed. The problems of a possible isotensor component in the electromagnetic current, the time-reversal invariance of the electromagnetic interactions and the photoproduction of the Roper resonance are considered in detail.

21 data tables

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Measurement of Polarized Target Asymmetry on $\gamma n \to \pi^- p$ Around the Second Resonance Region

Fujii, K. ; Hayashii, H. ; Iwata, S. ; et al.
Nucl.Phys.B 187 (1981) 53-70, 1981.
Inspire Record 156223 DOI 10.17182/hepdata.34260

The polarized target asymmetry for γ n→ π − p was measured over the second resonance region from 0.55 to 0.9 GeV at pion c.m. angles between 60° and 120°. A double-arm spectrometer was used with a deuterated butanol target to detect both the pion and the proton, thus considerably improving the data quality. Including the new data in the amplitude analysis, the radiative decay widths of three resonances were determined more accurately than before. The results are compared with various quark models.

8 data tables

PHOTON ENERGY IS IN THE NEUTRON REST FRAME.

PHOTON ENERGY IS IN THE NEUTRON REST FRAME.

PHOTON ENERGY IS IN THE NEUTRON REST FRAME.

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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

No description provided.


Polarization of the recoil proton from the process gamma n ---> p pi- in deuterium for (theta pi)c.m.=90 degrees in the second-resonance region

Beneventano, M. ; D' Angelo, S. ; De Notaristefani, F. ; et al.
Lett.Nuovo Cim. 3S1 (1970) 840-844, 1970.
Inspire Record 64710 DOI 10.17182/hepdata.37344

None

1 data table

No description provided.


Photoproduction of charged pions on deuterium in the first resonance region

Von Holtey, G. ; Knop, G. ; Stein, H. ; et al.
Nucl.Phys.B 70 (1974) 379-389, 1974.
Inspire Record 94755 DOI 10.17182/hepdata.32319

Photoproduction of π + and π − on deuterium has been measured in the photon energy range from 240 to 400 MeV and for pion c.m. angles between 15° and 180°. The pions were analysed in angle and momentum by a magnetic spectrometer. From the measured π − / π + ratio, corrected for Coulomb interactions in the final state, differential cross sections of the reaction γ +n→ π − +p were calculated. Together with the π + photoproduction our data show no isotensor contribution. Comparison of our data with the recent experiments done on the inverse reaction shows no evidence of a violation of time reversal invariance. With the measured π + photoproduction on deuterium, a test of the spectator model has been made. Using the closure-approximation of Chew and Lewis our data agree within a range of ±10%.

6 data tables

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Single pi- photoproduction on neutrons in the energy region of the p(11), d(13), s(11) pion-nucleon resonances

Beneventano, M. ; D' Angelo, S. ; De Notaristefani, F. ; et al.
Nuovo Cim.A 19 (1974) 529-547, 1974.
Inspire Record 96708 DOI 10.17182/hepdata.37753

In this note we report the results obtained in a single-photoproduction experiment on neutrons in deuterium, with an experimental apparatus made of scintillation counters, spark chambers and a magnetic spectrometer; the explored energy region is one around the second resonance, that is (500÷900) MeV indicent γ-ray energy. We briefly describe the present situation of the phenomenological analysis of the single photoproduction in the second resonance region and compare the results of an analysis made by us with the results obtained by other authors; in particular the e.m. coupling of theP11 isobaric state found by us is large, in accordance with the results of some other authors.

1 data table

No description provided.


Measurement of the pi- p ---> n pi0 and pi- p ---> n gamma differential cross-sections near the resonance p(11)(1460)

Cheze, J.B. ; Codreanu, N. ; Hamel, J.L. ; et al.
Nucl.Phys.B 72 (1974) 365-375, 1974.
Inspire Record 94658 DOI 10.17182/hepdata.7810

The π − p→n γ and π − p→n π ° differential cross sections have been measured for −0.9< cos θ ∗ <−0.45 (θ ∗ c.m. scattering angle) at 475 MeV/ c and 550 MeV/ c incident momenta. The π − p→n γ measurement is a good check of the detailed balance principle in the electromagnetic interactions of hadrons at these energies and is in good agreement with Walker's analysis. On the other hand the π − p→ π °n extrapolated values of 180° allows one to verify that the phases of the A 1 2 and A 3 2 amplitudes are equal.

5 data tables

No description provided.

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BACKWARD CROSS SECTION ESTIMATED BY LEGENDRE POLYNOMIAL FIT.

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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

Axis error includes +- 6.6/6.6 contribution.

Axis error includes +- 6.2/6.2 contribution.

Axis error includes +- 6.0/6.0 contribution.

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PHOTOPRODUCTION OF PI- MESONS ON NEUTRONS INDUCED BY POLARIZED PHOTONS IN THE ENERGY INTERVAL 0.9-GEV - 1.65-GEV. (IN RUSSIAN)

Abramian, L.O. ; Aganyants, Aleksandr O. ; Adamian, F.V. ; et al.
Yad.Fiz. 32 (1980) 133-140, 1980.
Inspire Record 159786 DOI 10.17182/hepdata.18933

None

6 data tables

Axis error includes +- 10./10. contribution (DUE TO BEAM POLARIZATION UNCERTAINTY).

D(SIG)/D(OMEGA)=(D(SIG(O))/D(OMEGA)+D(SIG(C))/D(OMEGA))/2, WHERE (O) AND (C) DENOTES GAMMA POLARIZATION ORTHOGONAL AND COPLANAR TO THE REACTION PLANE.

Axis error includes +- 10./10. contribution (DUE TO BEAM POLARIZATION UNCERTAINTY).

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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

Axis error includes +- 6/6 contribution.

Axis error includes +- 4.5/4.5 contribution.

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

Axis error includes +- 6.3/6.3 contribution.

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

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).

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).

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).

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Measurement of Recoil Proton Polarization in the Process of $\pi^-$ Photoproduction From Neutrons in the Energy Range Between 700-{MeV} and 1200-{MeV}

Takeda, H. ; Arai, I. ; Fujii, T. ; et al.
Nucl.Phys.B 168 (1980) 17-31, 1980.
Inspire Record 131380 DOI 10.17182/hepdata.34512

The recoil proton polarization for γ n → π − p was measured around the third resonance region. Both momentum vectors of the proton and the pion were determined by the magnetic spectrometers. The proton polarization was measured by means of proton-carbon scattering in the polarization analyzer located behind the proton spectrometer. Below 900 MeV incident photon energy, our data are consistent with the other existing experimental data ( θ π ∗ = 90° ) and the predictions of partial-wave analyses. Above 1000 MeV, however, a large discrepancy was observed between our data and the predictions of the partial-wave analyses. The discrepancy stands out as the pion c.m. angle increases. A new partial-wave analysis was made for γ n → π − p including our polarization data, and the accuracy of the experimentally determined electromagnetic coupling constant of the third resonances were greatly improved. In particular, a finite amount of the helicity 3 2 amplitude for the γ n → F 15 (1688) resonance was obtained against the predictions of the quark models, by Copley, Karl and Obryk and by Feynman, Kislinger and Ravendal but in agreement with the relativistic quark models of Sugimoto and Toya, and Kubota and Ohta.

1 data table

No description provided.


A Study of Charged Pseudoscalar Meson Photoproduction From Hydrogen and Deuterium With 16-{GeV} Linearly Polarized Photons

Quinn, D.J. ; Rutherfoord, J.P. ; Shupe, M.A. ; et al.
Phys.Rev.D 20 (1979) 1553, 1979.
Inspire Record 140543 DOI 10.17182/hepdata.24208

The asymmetries in forward π−N, π−Δ, and K+−(Λ+Σ) photoproduction have been measured with a 16-GeV linearly polarized beam. The experimental method and the procedures for extracting cross sections and asymmetries from the data are discussed in detail. Information on the energy and momentum-transfer dependence of cross sections for natural- and unnatural-parity exchange, interference between exchanges of opposite G parity, and vector-meson dominance is obtained and discussed.

7 data tables

ASYMMETRIES AND DIFFERENTIAL CROSS SECTIONS FOR PION-NUCLEON PHOTOPRODUCTION WERE FIRST PUBLISHED IN D. J. SHERDEN ET AL., PRL 30, 1230 (1973) AND PRL 31, 667 (1973) (ERRATUM). THESE SLIGHTLY REVISED NUMBERS ARE INCLUDED IN THE RECORD OF THE 1973 PAPER.

No description provided.

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Pi+ photoproduction from hydrogen with polarized photons

Bar-Yam, Z. ; De Pagter, J. ; Dowd, J. ; et al.
Phys.Rev.Lett. 25 (1970) 1053-1056, 1970.
Inspire Record 62861 DOI 10.17182/hepdata.21600

The reaction γ⊥,∥p→π+n has been studied with linearly polarized photons of energy 3.0 GeV at −t values between 0.15 and 1.2 (GeVc)2. The asymmetry A+=(dσ⊥−dσ∥)(dσ⊥+dσ∥) is found to be positive throughout this four-momentum-transfer range, implying the dominance of natural parity exchange in the t channel. Comparison of dσ⊥(γ⊥p→π+n) and dσ⊥p→π−p) from a previous experiment indicates strong interference between the isoscalar and isovector photon amplitudes for photons polarized perpendicular to the production plane.

3 data tables

No description provided.

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Charged-pi photoproduction at 180 degress in the energy range between 300 and 1200 mev

Fujii, T. ; Okuno, H. ; Orito, S. ; et al.
Phys.Rev.Lett. 26 (1971) 1672-1675, 1971.
Inspire Record 68981 DOI 10.17182/hepdata.21616

The differential cross sections at 180° for the reactions γ+p→π++n and γ+n→π−+p were measured using a magnetic spectrometer to detect π± mesons. In order to reduce the spread of energy resolution due to the nucleon motion inside the deuteron, a photon difference method was employed with a 50-MeV step for the reaction γ+n→π−+p. The data show structures at the second- and the third-resonance regions for both reactions. A simple phenomenological analysis was made for fitting the data, and the results are compared with those of previous analyses.

2 data tables

No description provided.

No description provided.


Production of single negative pions from deuterium with polarized photons

Bar-Yam, Z. ; De Pagter, J. ; Dowd, J. ; et al.
Phys.Rev.Lett. 24 (1970) 1078-1081, 1970.
Inspire Record 62952 DOI 10.17182/hepdata.21628

The asymmetry A=(dσ⊥−dσ∥)(dσ⊥+dσ∥) of the differential cross section for the reaction γd→π−pp has been studied with linearly polarized photons of 3.0 GeV at squared four-momentum-transfers between 0.15 and 2.0 (GeV/c)2. The asymmetry was found to be positive at −t values below 0.3 (GeV/c)2, dipping to negative values between 0.4 and 0.6 (GeV/c)2, and then rising again to positive values above 0.7 (GeV/c)2.

1 data table

Axis error includes +- 11/11 contribution.


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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Negative-pion photoproduction from neutrons by linearly polarized photons in the first resonance region

Kondo, K. ; Miyachi, T. ; Ukai, K. ; et al.
Phys.Rev.D 9 (1974) 529-533, 1974.
Inspire Record 93115 DOI 10.17182/hepdata.21954

The angular dependence of the asymmetry for negative-pion photoproduction on neutrons by linearly polarized photons has been measured for photon energies 260, 300, 350, 400, 450, and 500 MeV at center-of-mass angles 60°, 75°, 90°, 150°, and 120°. The results are compared with theoretical models of low-energy single-pion photoproduction. The observed asymmetry below 400 MeV shows good agreement with predictions of dispersion-theoretical models by Berends, Donnachie, and Weaver and by Schwela. The asymmetry values in the 400-500 MeV energy region suggest that smaller M1− amplitude is more favorable.

6 data tables

No description provided.

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Pi- photoproduction from deuterium at laboratory energies 600 to 1250 mev

Scheffler, P.E. ; Walden, P.L. ;
Phys.Rev.Lett. 24 (1970) 952-954, 1970.
Inspire Record 62962 DOI 10.17182/hepdata.32219

The differential cross section for the reaction γ+n→π−+p was measured for laboratory photon energies between 600 and 1250 MeV, using a liquid deuterium target. The internal nucleon momentum distribution of the deuteron was used to calculate the major effect of using deuterium as a neutron target. The data show that the amplitude to excite the F15(1688) resonance is small, in agreement with a recent quark-model prediction.

29 data tables

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Photoproduction of Pions on Polarized Protons and Neutrons in the Second Resonance Region

Althoff, K.H. ; Gies, M. ; Herr, H. ; et al.
Nucl.Phys.B 131 (1977) 1-6, 1977.
Inspire Record 119995 DOI 10.17182/hepdata.35224

Measurements of the target asymmetry T = ( σ ↑ − σ ↓)/( σ ↑ + σ ↓) for the reactions γ p → π + n and γ n → π − p at a fixed photon energy of 850 MeV and pion c.m. angles between 70° and 150° are reported. The data are compared to the previously measured angular distribution at 700 MeV.

2 data tables

No description provided.

No description provided.


Photoproduction of Negative Pions on Polarized Neutrons in the Region of the Second Resonance

Althoff, K.H. ; Conrad, R. ; Gies, M. ; et al.
Nucl.Phys.B 116 (1976) 253-260, 1976.
Inspire Record 109397 DOI 10.17182/hepdata.35639

A polarized neutron target was used at the Bonn 2.5 GeV Synchrotron to measure the target asymmetry for the reaction γ n↑→ π − p at a fixed photon energy of 700 MeV and pion c.m. angles between 50° and 140°. The pions were detected in a large aperture magnetic spectrometer. The data show a structure which is quite different from the distribution previously measured for the reaction γ p↑→ π + n.

1 data table

No description provided.


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 (?////).

No description provided.


A Search for Delta I = 2 Electromagnetic Currents in Pion Photoproduction

Clifft, R.W. ; Gabathuler, E. ; Littenberg, L.S. ; et al.
Phys.Rev.Lett. 33 (1974) 1500, 1974.
Inspire Record 90951 DOI 10.17182/hepdata.21245

Differential cross sections for the reactions γp→π0p, π+n and γn→π−p, π0n were measured in a single experiment using tagged photons in the energy region 240-450 MeV incident on H21 and H22 targets. Results of the measurements of the ratios π0nπ0p and π−pπ+n are presented. The ratio of isotensor to isovector amplitude is found to be 0.00±0.02.

15 data tables

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ASYMMETRIES IN CHARGED PION PHOTOPRODUCTION ON NUCLEONS BY 16-GeV POLARIZED PHOTONS

Sherden, D. ; Siemann, R. ; Sinclair, Charles K. ; et al.
Phys.Rev.Lett. 30 (1973) 1230, 1973.
Inspire Record 81026 DOI 10.17182/hepdata.21357

Asymmetries in charged-pion photoproduction from hydrogen and deuterium have been measured with 16-GeV linearly polarized photons. Considerable energy dependence is seen in the natural-parity contribution to the π−π+ ratio from deuterium, and in the unnatural-parity part of the cross section for γn→π−p. The energy dependence of this latter cross section is consistent with the expected from a conventional pion Regge trajectory.

5 data tables

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Measurement of Asymmetries in Polarized gamma + n --> pi + n, with E(gamma) from 600-MeV to 900-MeV

Knies, G. ; Oberlack, H. ; Rittenberg, A. ; et al.
Phys.Rev.D 10 (1974) 2778, 1974.
Inspire Record 90220 DOI 10.17182/hepdata.24943

We report on the measurement of asymmetries in the single-pion photoproduction reactions γp→nπ+, γp→pπ0, and γn→pπ−, induced by linearly polarized photons of energies from 610 to 940 MeV. The experiment was carried out using the back-scattered laser beam and the 82-in. dubble chamber at SLAC. We compare the new data with predictions from a partial-wave analysis.

13 data tables

No description provided.

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Photoproduction of Negative Pions on a Polarized Neutron Target in the Resonance Region

Althoff, K.H. ; Beckschulze, H. ; Conrad, R. ; et al.
Nucl.Phys.B 96 (1975) 497-508, 1975.
Inspire Record 99642 DOI 10.17182/hepdata.31932

At the Bonn 2.5 GeV electron synchrotron the first measurements of the target asymmetry for the reaction γ + n ↑ → π − + p have been performed. The negative pions were detected in a magnetic spectrometer at a constant pion c.m. angle of 40° and photon energies between 0.45 GeV and 2.0 GeV. Deuterated butanol was used as target material. The polarization of the deuterons was about 16%. The results show a significant difference from the previously measured π + asymmetry.

1 data table

No description provided.


Photoproduction of negative pions on neutrons at photon energies between 0.2-GeV and 2.0-GeV

The Aachen-Berlin-Bonn-Hamburg-Heidelberg-Muenchen collaboration Hilpert, H.G. ; Lauscher, P. ; Matziolis, M. ; et al.
Nucl.Phys.B 8 (1968) 535-544, 1968.
Inspire Record 56298 DOI 10.17182/hepdata.32389

Total and differenial cross sections of the reaction γ +n→p+ π − have been determined for photon-energies between 0.2 and 2.0 GGeV. Below 500 MeV the differential cross sections are compared with theoretical predictions derived from fixed-momentum-transfer dispersion relations.

30 data tables

Axis error includes +- 0.0/0.0 contribution (5 TO 8////).

Axis error includes +- 0.0/0.0 contribution (5 TO 8////).

Axis error includes +- 0.0/0.0 contribution (5 TO 8////).

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Single Photoproduction of Negative Pions from Neutrons by Linearly Polarized Photons in the Region of the First Pion-Nucleon Resonance

Ganenko, V.B. ; Gorbenko, V.G. ; Zhebrovsky, Yu.V. ; et al.
Sov.J.Nucl.Phys. 23 (1976) 511-515, 1976.
Inspire Record 116406 DOI 10.17182/hepdata.39784

None

6 data tables

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

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

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

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Photoproduction of Charged pi Mesons from Hydrogen and Deuterium in the Energy Range Between 250-MeV and 790-MeV

Fujii, T. ; Kondo, T. ; Takasaki, F. ; et al.
Nucl.Phys.B 120 (1977) 395-422, 1977.
Inspire Record 108476 DOI 10.17182/hepdata.8405

The differential cross sections for γ p→ π + n from hydrogen and the π − π + ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γ n→ π − p was obtained as a product of d σ d Ω (γ p →π + n ) and the π − π + ratio. The overall features in the cross sections of the two reactions, γ p→ π + n and γ n→ π − p, and in the ratios, π − π + , agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π − p→ γ n, no apparent violation of time-reversal invariance was observed.

112 data tables

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Total and Partial gamma d, gamma n and gamma p Cross-Sections at 7.5-GeV

Alexander, G. ; Gandsman, J. ; Jacobs, L.D. ; et al.
Nucl.Phys.B 68 (1974) 1-11, 1974.
Inspire Record 94509 DOI 10.17182/hepdata.32388

Total and partial γd, γp and γn reactions were studied in the SLAC 82 inch deuterium-filled bubble chamber, which was exposed to a linearly polarized photon beam at an energy of 7.5 GeV. We report total, topological and channel cross sections for these reactions. The γn average charge multiplicity was found to be one unit of charge less than the γp average charge multiplicity. The isoscolar-isovector interference term as calculated by comparing the γp charge symmetric reactions is found to be small.

3 data tables

No description provided.

CHARGE MULTIPLICITY TOPOLOGICAL CROSS SECTIONS.

No description provided.


Measurement of the Differential Cross-Section in Photoproduction of pi- Mesons

Sternemann, Klaus-Peter ;
BONN-IR-76-45, 1976.
Inspire Record 111853 DOI 10.17182/hepdata.50171

None

19 data tables

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Photoeinfacherzeugung geladener $\pi$-Mesonen bei kleinen Impulsüberträgen im Energiebereich zwischen 2.6 und 6.0 GeV

Heide, Peter ;
DESY-F-35-69-01, 1969.
Inspire Record 917751 DOI 10.17182/hepdata.21701

None

6 data tables

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RATIO OF pi- TO pi+ PHOTOPRODUCTION FROM DEUTERIUM AT 8-GeV AND 16-GeV

Boyarski, A. ; Diebold, Robert E. ; Ecklund, Stanley D. ; et al.
Phys.Rev.Lett. 21 (1968) 1767-1769, 1968.
Inspire Record 52651 DOI 10.17182/hepdata.21722

We have studied the ratio R=[dσ(γd→π−pp)dt][dσ(γd→π+nn)dt]−1 at 8 and 16 GeV for momentum transfers |t| from about 0.001 to 1.3 GeV2. R is close to unity for |t|<mπ2, but falls very rapidly with increasing |t|, passing through ½ near |t|=0.1 GeV2 and having a minium value of about 13 near |t|=0.4 GeV2; it slowly increases at larger momentum transfers. These results are similar to those obtained in other laboratories at 3.4 and 5 GeV. This implies considerable interference between the isoscalar and isovector photon amplitudes.

2 data tables

No description provided.

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Pi-+ photoproduction in forward direction

Ito, A. ; Loe, R. ; Loh, E.C. ; et al.
Phys.Rev.Lett. 24 (1970) 687-690, 1970.
Inspire Record 62934 DOI 10.17182/hepdata.21670

The ratio of π− to π+ off deuterium was measured as a function of incident photon energy from 600 to 1700 MeV in the forward direction. The ratio shows a broad dip around a center-of-mass energy of 1700 MeV, resulting presumably from the collective effect of several isospin-½ resonances in this energy region. Such a change in the ratio is reflected in the rapid variation of the isoscalar photoproduction amplitude since we found the isovector photoproduction amplitude to be a relatively smooth function decreasing slowly with increasing incident photon energy.

1 data table

No description provided.


Photoproduction of Single Charged Pions from Deuterium and Hydrogen

Bar-Yam, Z. ; de Pagter, J. ; Hoenig, M.M. ; et al.
Phys.Rev.Lett. 19 (1967) 40-42, 1967.
Inspire Record 52325 DOI 10.17182/hepdata.21751

Differential cross sections for the photoproduction of single charged pions from deuterium and hydrogen have been measured at pion center-of-mass angles between 30° and 90° and at photon energies between 3.0 and 3.7 GeV. The ratio of π− to π+ cross sections from deuterium is found to be appreciably smaller than 1.

4 data tables

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The Production of Charged Photomesons from Deuterium and Hydrogen. I

White, R.S. ; Jacobson, M.J. ; Schulz, A.G. ;
Phys.Rev. 88 (1952) 836-850, 1952.
Inspire Record 944937 DOI 10.17182/hepdata.26456

Hydrogen and deuterium gases have been bombarded in a gas target at a temperature of 77°K and at a pressure of about 140 atmospheres by the 318±10 Mev "spread-out" bremsstrahlung photon beam of the Berkeley electron synchrotron. The charged π-mesons which were produced were collimated at angles of 45°, 90°, and 135° to the beam direction. The π+ mesons were detected with trans-stilbene scintillation crystals using πμ, πβ, and πμβ delayed coincidences and π+ and π− mesons were detected with Ilford C-2 200-micron nuclear emulsions. The ratios of the numbers of π− to π+ mesons produced in deuterium were 0.96±0.10, 1.09±0.12, and 1.21±0.17 for the angles of 45°, 90°, and 135°, respectively. No variation of the ratio with meson energy, outside statistics, was observed. Absolute values for the π+ meson energy distribution functions from hydrogen and deuterium per "equivalent quantum" have been measured at each of the above production angles. The differential and total cross sections have been obtained by integrating over energy and angle, respectively. The experimental ratios of the deuterium to hydrogen cross sections are in good agreement with the phenomenological theory of Chew and Lewis when the Hulthén deuteron function with β=6α is used in the initial state, plane waves are used for the nucleons in the final state, and the bremsstrahlung cutoff is taken into account. The statistics of the data are, however, not sufficient to determine the amount of spin interaction. The excitation functions for hydrogen and deuterium and points on the angular distribution curves in the center-of-mass system have been obtained. An upper limit of 0.08 of the charged π-meson cross section was obtained for μ-meson production from deuterium.

1 data table

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Charged-Pion Photoproduction from Deuterium with Polarized Bremsstrahlung

Liu, F.F. ; Drickey, D.J. ; Mozley, R.F. ;
Phys.Rev. 136 (1964) B1183-B1186, 1964.
Inspire Record 1186786 DOI 10.17182/hepdata.26721

Measurements have been made on the ratio of pion-production cross sections at right angles to and along the photon electric-field vector. The positive and negative pions were first momentum-analyzed and counted by means of a counter telescope. Data have been taken at 45, 90, and 135° in the c.m. system, and at proton energies of 225, 330, and 450 MeV. A comparison of the data is made with the dispersion-relation calculation of McKinley.

2 data tables

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Photoproduction of Charged Mesons from Free Nucleons for Bombarding Gamma-Ray Energies Near 275 MeV

Garelick, D. ; Cooperstein, G. ;
Phys.Rev. 136 (1964) B201-B213, 1964.
Inspire Record 944969 DOI 10.17182/hepdata.26720

The differential cross section for the photoproduction of a π− meson from the neutron bound in the deuteron was measured for pion laboratory angles of 76°, 96°, and 118° at incident gamma-ray energies in the region of 275 MeV. The π− meson and the high-energy proton were detected. The pion momentum and angle were measured by sets of spark chambers situated in front of and behind a magnetic field. The proton angle and range were also measured with spark chambers. To calculate "free" neutron cross sections from our data, we used a modified version of the extrapolation method suggested by Chew and Low. By observing the π+ only, the differential cross section for π+ photoproduction from hydrogen also was measured. As determined by this experiment, the differential cross section for photoproduction of a π− meson from a "free" neutron and the differential cross section for photoproduction of a π+ meson from hydrogen are as follows: Eγlab≃275 MeV These results disagree with the dispersion theory predictions of Chew, Goldberger, Low, and Nambu. They also disagree with McKinley's dispersion theory calculations which include a bipion or ρ-meson term in the production amplitudes.

2 data tables

No description provided.

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Photoproduction of Low-Energy Charged Pions from Deuterium

Burq, J.P. ; Walker, J.K. ;
Phys.Rev. 132 (1963) 447-454, 1963.
Inspire Record 944972 DOI 10.17182/hepdata.26772

Accurate measurements have been made of the π−π+ photoproduction ratio on deuterium, in the gammaray energy range 165-210 MeV, for several angles: 155°, 125°, 90° (center-of-mass system) and along Baldin's kinematical line. These last data are new contributions: π−π+=1.20±0.03 averaged between 165 and 180 MeV. The others are improvements of the accuracy of previous data. The comparison with Ball's theory, corrected for taking into account the I=12 phase shifts, gives for the coupling constant Λ for γ−π−p the value: 0.25<+Λe<0.75.

1 data table

No description provided.