$\pi^- P$ 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.

1 data table match query

No description provided.


Analyzing Power for $\pi^- P$ Charge Exchange and a Test of Isospin Invariance Up to $\eta$ Threshold

Wightman, J.A. ; Eichon, A.D. ; Kim, G.J. ; et al.
Phys.Rev.D 36 (1987) 3529-3532, 1987.
Inspire Record 255689 DOI 10.17182/hepdata.23322

The analyzing power for π−p→π0n has been measured at five incident momenta from 547 to 687 MeV/c using a transversely polarized target. Data were obtained with scintillation counters at 10 angles simultaneously covering the range −0.9≤cosθc.m.π≤0.9. Our results and those of Kim et al. are used for a model-independent test of isospin invariance which is based on the triangle inequalities applied to the transversity-up as well as the transversity-down cross sections. No evidence is found of isospin violation.

1 data table match query

No description provided.


Analyzing power for pi- p charge exchange in the backward hemisphere from 301-MeV/c to 625-MeV/c and a test of pi N partial wave analyses

Kim, G.J. ; Arends, J. ; Engelage, J. ; et al.
Phys.Rev.D 41 (1990) 733-743, 1990.
Inspire Record 301242 DOI 10.17182/hepdata.22935

The analyzing power of π−p→π0n has been measured for pπ=301−625 MeV/c with a transversely polarized target, mainly in the backward hemisphere. The final-state neutron and a γ from the π0 were detected in coincidence with two counter arrays. Our results are compared with predictions of recent πN partial-wave analyses by the groups of Karlsruhe-Helsinki, Carnegie-Mellon University-Lawrence Berkeley Laboratory (CMU-LBL), and Virginia Polytechnic Institute (VPI). At the lower incident energies little difference is seen among the three analyses, and there is excellent agreement with our data. At 547 MeV/c and above, our data strongly favor the VPI phases, and disagree with Karlsruhe-Helsinki and CMU-LBL analyses, which are the source of the πN resonance parameters given in the Particle Data Group table.

3 data tables match query

Axis error includes +- 5/5 contribution (Uncertainty in background normalisation).

Axis error includes +- 5/5 contribution (Uncertainty in background normalisation).

Axis error includes +- 5/5 contribution (Uncertainty in background normalisation).


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 match query

Charge exchange cross section from PWA.

PI- P --> GAMMA N cross section.

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


Differential Cross-sections for $\pi^+ P$ and $\pi^- P$ Elastic Scattering From 378-{MeV}/c to 687-{MeV}/c

Sadler, M.E. ; Briscoe, W.J. ; Fitzgerald, D.H. ; et al.
Phys.Rev.D 35 (1987) 2718-2735, 1987.
Inspire Record 250023 DOI 10.17182/hepdata.23362

Differential cross sections have been measured for π+p and π−p elastic scattering at 378, 408, 427, 471, 509, 547, 586, 625, 657, and 687 MeV/c in the angular range -0.8<cosθc.m.<0.8. The scattered pion and recoil proton were detected in coincidence using scintillation-counter hodoscopes. A liquid-hydrogen target was used except for measurements at forward angles, in which a CH2 target was used. Statistical uncertainties in the data are typically less than 1%. Systematic uncertainties in acceptance and detection efficiency are estimated to be 1%. Absolute normalization uncertainties are 2–3 % for most of the data. The measurements are compared with previous data and with the results of recent partial-wave analyses. The data are fit with Legendre expansions from which total elastic cross sections are obtained.

13 data tables match query

Normalisation uncertainty = 4.1 pct.

Normalisation uncertainty = 2.1 pct.

Normalisation uncertainty = 3.6 pct.

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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.

4 data tables match query

Axis error includes +- 4.5/4.5 contribution.

Axis error includes +- 4.2/4.2 contribution.

Axis error includes +- 4.5/4.5 contribution.

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ELASTIC PI+- P SCATTERING FROM 378-MEV/C TO 687-MEV/C

Sadler, M.E. ; Seftor, C.J. ; Borcherding, F.O. ; et al.
Phys.Lett.B 119 (1982) 69-71, 1982.
Inspire Record 184515 DOI 10.17182/hepdata.30826

Differential cross sections for π ± p→ π ± p have been measured at P π between 378 and 687 MeV / c at 9 angles in the range −0.8⩽cos θ c.m. ⩽0.6. Scattered pions and recoil protons were detected in coincidence using scintillation counter hodoscopes. For almost all of the data the statistical and normalization uncertainties are each less than 2%. Our measurements are compared with existing data and the results of recent partial wave analyses.

5 data tables match query

No description provided.

No description provided.

No description provided.

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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.

3 data tables match query

No description provided.

No description provided.

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.

1 data table match query

Axis error includes +- 6.6/6.6 contribution.


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.

2 data tables match query

Measured total cross section. Statistical errors only.

Differential angular distributions of the 2PI0 system for the LH2 data at beam momenta 355 to 472 MeV/c. Statistical errors only.