Measurement of the differential cross-section for pi- p ---> n pi0 at 317, 452, and 491 mev/c

Berardo, P.A. ; Haddock, R.P. ; Nefkens, B.M.K. ; et al.
Phys.Rev.D 6 (1972) 756-766, 1972.
Inspire Record 73968 DOI 10.17182/hepdata.3558

Seventeen differential cross sections of the pion-nucleon charge-exchange reaction have been measured at total center-of-mass energies of 1245, 1337, and 1363 MeV. Most measurements are based on the neutron-photon coincidence method, using carefully calibrated neutron counters and an efficient, large-area photon detector. The results are used to test the predictions of charge independence, with which they agree. The results also confirm the Ayed-Bareyre-Sonderegger phase-degeneracy hypothesis at θ̃π0=180°.

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Pi p elastic scattering from 88 to 292 mev

Bussey, P.J. ; Carter, J.R. ; Dance, D.R. ; et al.
Nucl.Phys.B 58 (1973) 363-377, 1973.
Inspire Record 83985 DOI 10.17182/hepdata.6770

Differential cross sections for π + p and π − p elastic scattering have been measured with an accuracy of typically ±2% at 10 and 9 energies respectively in the range 88 to 292 MeV of lab kinetic energy.

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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.

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PRECISE MEASUREMENT OF THE PION CHARGE EXCHANGE FORWARD DIFFERENTIAL CROSS-SECTION AT 522-MEV/C

Gaille, F.C. ; Highland, V.L. ; Auerbach, L.B. ; et al.
Phys.Rev.D 30 (1984) 2408-2410, 1984.
Inspire Record 215121 DOI 10.17182/hepdata.23596

A precise measurement of the differential cross section at zero degrees for the pion charge-exchange reaction π−p→π0n at pπ=522 MeV/c has been made. The result is dσdΩ (0∘)=4.32±0.11 mb/sr.

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Measurement of Pion Proton Bremsstrahlung for Pions at 299-{MeV}

Meyer, C.A. ; Amsler, Claude ; Bosshard, A. ; et al.
Phys.Rev.D 38 (1988) 754-767, 1988.
Inspire Record 268867 DOI 10.17182/hepdata.23271

We have measured the fivefold differential cross section d5σ/dΩπdΩγdEγ for the process π+p→π+pγ with incident pions of energy 299 MeV. The angular regions for the outgoing pions (55°≤θlabπ≤95°), and photons (θlabγ=241°±10°) in coplanar geometry are selected to maximize the sensitivity to the radiation from the magnetic dipole moment of the Δ++(1232) resonance. At low photon energies, the data agree with the soft-photon approximation to pion-proton bremsstrahlung. At forward pion angles the data agree with older data and with the latest theoretical calculations for 2.3μp≤μΔ≤3.3μp. However at more backward pion angles where no data existed, the predictions fail.

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Recoil Proton Polarization in $\pi P$ Elastic Scattering at 547-{MeV}/c and 625-{MeV}/c

Seftor, C.J. ; Adrian, S.D. ; Briscoe, W.J. ; et al.
Phys.Rev.D 39 (1989) 2457-2463, 1989.
Inspire Record 282265 DOI 10.17182/hepdata.23234

The polarization of the recoil proton in π+p and π−p elastic scattering using a liquid-hydrogen target has been measured for backward angles at 547 and 625 MeV/c. The scattered pion and recoil proton were detected in coincidence using the large-acceptance spectrometer to detect and analyze the momentum of the pions and the JANUS polarimeter to identify and measure the polarization of the protons. Results from this experiment agree with other measurements of the recoil polarization, with analyzing-power data previously taken by this group, and with predictions of partial-wave analyses.

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$\pi^- P$ Charge Exchange Analyzing Power From 547-{MeV}/c to 687-{MeV}/c

Wightman, J.A. ; Eichon, A.D. ; Kim, G.J. ; et al.
Phys.Rev.D 38 (1988) 3365-3374, 1988.
Inspire Record 270260 DOI 10.17182/hepdata.23237

The π−p charge-exchange analyzing power has been measured from 547 to 687 MeV/c in the center-of-mass angular range -0.9≤cosθ̃π≤0.9 using a transversely polarized target. The recoil neutron was detected in coincidence with a photon from π0 decay. The results are compared with the three recent partial-wave analyses (PWA’s); the VPI analysis is most consistent with our measured distributions except at 687 MeV/c where no PWA agrees with our data. The charge-exchange transversity cross sections are evaluated using the differential cross sections of Borcherding et al. These transversity cross sections are used in conjunction with earlier π±p data by our group to test the triangle inequalities which are a model-independent test of isospin invariance. Our data satisfy these inequalities everywhere; in contrast, Abaev et al. have reported a violation of more than 5 standard deviations at 685 MeV/c.

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Measurement of the pi- p ---> 3 pi0 n total cross-section from threshold to 0.75-GeV/c

Starostin, A. ; Nefkens, B.M.K. ; Manley, D.M. ; et al.
Phys.Rev.C 67 (2003) 068201, 2003.
Inspire Record 620818 DOI 10.17182/hepdata.25279

We report a new measurement of the π−p→3π0n total cross section from threshold to pπ=0.75GeV/c. The cross section near the N(1535)12− resonance is only a few μb after subtracting the large η→3π0 background associated with π−p→ηn. A simple analysis of our data results in the estimated branching fraction B[S11→πN(1440)12+]=(8±2)%. This is the first such estimate obtained with a three-pion production reaction.

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Total Cross Sections for Negative Pions on Protons at 230, 290, 370, 427, and 460 Mev

Caris, John C. ; Goodwin, Lester K. ; Kenney, Robert W. ; et al.
Phys.Rev. 122 (1961) 262-264, 1961.
Inspire Record 944986 DOI 10.17182/hepdata.26810

Total cross sections for negative pions on protons were measured at laboratory energies of 230, 290, 370, 427, and 460 Mev. The measurements were made in the same pion beams as and at energies identical with those of our π−−p differential scattering experiments. Comparisons of the total and differential scattering can be made with the dispersion theory at a given energy without introducing the systematic errors that would normally enter due to uncertainties in the parameters of more than one pion beam. The measured total cross sections are found to agree within statistics with other measured values, and with the sums of elastic, inelastic, and charge-exchange cross sections measured at this laboratory. The results are:

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Elastic Scattering of Negative Pions by Protons at 230, 290, 370, and 427 Mev

Goodwin, Lester K. ; Kenney, Robert W. ; Perez-Mendez, Victor ;
Phys.Rev. 122 (1961) 655-664, 1961.
Inspire Record 944985 DOI 10.17182/hepdata.26809

The elastic differential cross section for the scattering of negative pions by hydrogen was measured at laboratory-system pion kinetic energies of 230, 290, 370, and 427 Mev. The elastically scattered pions were detected by a counter telescope which discriminated against recoil protons and inelastic pions on the basis of range. Differential cross sections were obtained at nine angles for each energy and were fitted by a least-squares program to a series of Legendre polynomials. At the three higher energies, D waves are required to give satisfactory fits to the data. The real parts of the forward-scattering amplitudes calculated from this experiment are in agreement with the predictions of dispersion theory. The results of this experiment, in conjunction with data from other pion-nucleon scattering experiments, support the hypothesis of charge independence at these higher energies.

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Cross-section Measurement of $\pi^- p \to \pi^- \pi^+ n$ Reaction Near Threshold

The OMICRON collaboration Kernel, G. ; Korbar, D. ; Krizan, P. ; et al.
Phys.Lett.B 216 (1989) 244-248, 1989.
Inspire Record 264989 DOI 10.17182/hepdata.29858

Result of cross section measurements for the reaction π − p → π − π + n are presented. They cover a range of incident pion momenta between 295 and 450 MeV/ c . It is the first time that the cross section has been measured so close to threshold. The experiment was performed with Omicron, a large-solid-angle spectrometer, which enables a measurement of the full set of kinematic variables. In the region of overlap there is a good agreement with other experiments. The extracted value for the chiral-symmetry-breaking parameter ξ is seen to be largely extrapolition dependent but the measured value of -0.5±0.8 leaves Weinberg's prediction of ξ =0 the only remaining choice.

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OBSERVATION OF INVERSE ELECTROPRODUCTION OF PIONS ON C-12 NUCLEUS AT 164-MeV PION ENERGY AND DETERMINATION OF F1(v) NUCLEON FORM-FACTOR

Alekseev, G.D. ; Blokhintseva, T.D. ; Karpukhin, V.V. ; et al.
Sov.J.Nucl.Phys. 46 (1987) 801, 1987.
Inspire Record 247868 DOI 10.17182/hepdata.38865
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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%.

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Measurement of pi- p ---> pi0 pi0 n from threshold to p(pi-) 750-MeV/c

The Crystal Ball collaboration Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev.C 69 (2004) 045202, 2004.
Inspire Record 647544 DOI 10.17182/hepdata.25355

Reaction π−p→π0π0n has been measured with high statistics in the beam momentum range 270–750MeV∕c. The data were obtained using the Crystal Ball multiphoton spectrometer, which has 93% of 4π solid angle coverage. The dynamics of the π−p→π0π0n reaction and the dependence on the beam energy are displayed in total cross sections, Dalitz plots, invariant-mass spectra, and production angular distributions. Special attention is paid to the evaluation of the acceptance that is needed for the precision determination of the total cross section σt(π−p→π0π0n). The energy dependence of σt(π−p→π0π0n) shows a shoulder at the Roper resonance [i.e., the N(1440)12+], and there is also a maximum near the N(1520)32−. It illustrates the importance of these two resonances to the π0π0 production process. The Dalitz plots are highly nonuniform; they indicate that the π0π0n final state is dominantly produced via the π0Δ0(1232) intermediate state. The invariant-mass spectra differ much from the phase-space distributions. The production angular distributions are also different from the isotropic distribution, and their structure depends on the beam energy. For beam momenta above 550MeV∕c, the density distribution in the Dalitz plots strongly depends on the angle of the outgoing dipion system (or equivalently on the neutron angle). The role of the f0(600) meson (also known as the σ) in π0π0n production remains controversial.

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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.

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Elastic scattering of 360 MeV positive $\pi$ mesons by protons

Mitin, N.A. ; Grigor'ev, E.L. ;
Sov.Phys.JETP 5 (1957) 378, 1957.
Inspire Record 1387578 DOI 10.17182/hepdata.39796

Photographic plates were used to study the angular distribotion of 360 plus or minus 10 Mev pi /sup +/ mesons elastically scattered by protons. The differential cross sections derived from 218 scattering events for SP analysis and for SPD analysis are given. The phase shifts which correspond to these distributions are also given.

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Measurements of the pi- p --> pi0 n Forward Scattering Cross-Section in the Energy Region 400-MeV-600-MeV

Kravtsov, A.V. ; Kuzmin, L.A. ; Nemozhenko, O.N. ; et al.
Nucl.Phys.B 140 (1978) 279-284, 1978.
Inspire Record 135966 DOI 10.17182/hepdata.34984

The forward charge-exchange differential cross section has been measured using two Čerenkov spectrometers at five energies of incident pions. The resulting cross-section values are 4.02 ± 0.22, 3.61 ± 0.13, 4.19 ± 0.13, 3.91 ± 0.12, 3.02 ± 0.14 mb/sr at incident pion energies 400, 450, 500, 550 and 600 MeV, respectively. These values are in a good agreement with dispersion-relation predictions.

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PHASE SHIFT ANALYSIS OF pi+ p SCATTERING IN THE REGION 194-MeV - 600-MeV

Abaev, V.V. ; Kruglov, S.P. ; Nichitiu, F. ;
Z.Phys.A 322 (1985) 603-610, 1985.
Inspire Record 201692 DOI 10.17182/hepdata.38008

An energy-independent phase-shift analysis ofπ+p-scattering has been carried out at 16 energies in the region 194–600 MeV. The new data on elastic polarization, obtained in LNPI up to 1983, were included.

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Measurement of the reaction pi+ p ---> pi+ pi+ n near threshold

The OMICRON collaboration Kernel, G. ; Korbar, D. ; Krizan, P. ; et al.
Z.Phys.C 48 (1990) 201-208, 1990.
Inspire Record 297700 DOI 10.17182/hepdata.15134

The reaction π+p→π+π+n was studied in the vicinity of the reaction threshold at ten incident pion beam momenta from 297 MeV/c to 480 MeV/c. From data angular distributions, invariant mass spectra and integrated cross-sections were deduced. The chiral symmetry breaking parameter as determined by this reaction equals to ξ=1.56±0.26±0.39, where the first error is experimental, while the latter reflects the uncertainty in the ansatz used in the extrapolation to the reaction threshold. A comparison with the other reaction channels of the reaction πp→ππN indicates that a single parameter (ξ) is not sufficient to describe low energy ππ interactions.

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SCATTERING OF 310-Mev POSITIVE PIONS BY PROTONS: EXPERIMENTS AND ANALYSIS

Rogers, Ernest H. ;
PhD Thesis, 1962.
Inspire Record 44325 DOI 10.17182/hepdata.18576
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PION-NUCLEON SCATTERING AT 310-MeV: NEUTRON POLARIZATION IN pi- p ---> pi0 n AND PHASE SHIFT ANALYSIS

Hill, Roger Eugene ;
PhD Thesis, 1964.
Inspire Record 44241 DOI 10.17182/hepdata.18615
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SCATTERING OF POSITIVE PIONS ON PROTONS AT 310-MEV: RECOIL NUCLEON POLARIZATION AND PHASE SHIFT ANALYSIS

Foote, James Herbert ;
PhD Thesis, 1960.
Inspire Record 44312 DOI 10.17182/hepdata.18619
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Measurement of the Polarization Parameter in $\pi^- p$ Scattering at 291.5-{MeV} and 308-{MeV}

Alder, J.C. ; Perroud, J.P. ; Tran, M.T. ; et al.
Lett.Nuovo Cim. 23 (1978) 381, 1978.
Inspire Record 130236 DOI 10.17182/hepdata.37401
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Contribution to the study of the interactions $\pi^{-}$p at 407 and 493 MeV : determination of cross sections of charged tracks, phase shift analysis in the elastic channel.

Derre, J. ;
PhD Thesis, Acad. Sci., Paris, 1969.
Inspire Record 1345881 DOI 10.17182/hepdata.39913
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Left-right Asymmetry in Inverse $\pi^-$ Photoproduction From a Transversely Polarized Proton Target

Kim, G.J. ; Adrian, S.D. ; Arends, J. ; et al.
Phys.Rev.Lett. 56 (1986) 1779-1782, 1986.
Inspire Record 232117 DOI 10.17182/hepdata.20259

Accurate measurements of the left-right asymmetry in π−p→γn at pπ=427−625 MeV/c with a transversely polarized target are reported. Results are compared with the predictions from the Arai and Fujii single-pion photoproduction partial-wave analysis and with data on the inverse process measured with a deuterium target. The agreement is poor, casting doubt on the correctness of the value for the radiative-decay amplitude of the neutral Roper resonance now in use.

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