Precision measurements of the pp ---> pi+ pn and pp ---> pi+ d reactions: Importance of long-range and tensor force effects

The COSY-GEM collaboration Budzanowski, A. ; Chatterjee, A. ; Hawranek, P. ; et al.
Phys.Rev.C 79 (2009) 061001, 2009.
Inspire Record 818511 DOI 10.17182/hepdata.52961

Inclusive measurements of pion production in proton--proton collisions in the forward direction were undertaken at 400 and 600 MeV at COSY using the Big Karl spectrograph. The high resolution in the $\pi^+$ momentum ensured that there was an unambiguous separation of the $pp\to {\pi}^+d/\pi^+pn$ channels. Using these and earlier data, the ratio of the production cross sections could be followed through the $\Delta$ region and compared with the predictions of final state interaction theory. Deviations are strongly influenced by long-range terms in the production operator and the tensor force in the final $pn$ system. These have been investigated in a realistic $pp\to\pi^+d/\pi^+pn$ calculation that includes $S \rightleftharpoons D$ channel coupling between the final nucleons. A semi-quantitative understanding of the observed effects is achieved.

6 data tables

Forward differential cross section for P P --> PI+ P N for beam momenta 1640 MeV.

Forward differential cross section for P P --> PI+ P N for beam momenta 1220 MeV.

Forward differential cross section for P P --> PI+ P N for beam momenta 955 MeV.

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Measurement of the Spin Correlation Parameters A(ll) and A(sl) for the Reaction $P P \to D \pi^+$ in the Energy Region 500-{MeV} - 800-{MeV}

Barlow, D.B. ; Saha, A. ; Seth, K.K. ; et al.
Phys.Rev.C 37 (1988) 1977-1986, 1988.
Inspire Record 242361 DOI 10.17182/hepdata.26282

Angular distributions of the spin-correlation parameters Asl and All for the reaction pp→π+d have been measured at pion center-of-mass angles 40°≤θπ+*≤130° at incident energies of 500, 650, and 800 MeV. Additional measurements of All were made at 600, 700, and 750 MeV. The results of the experiment are compared with the predictions of several unified coupled-channel calculations and partial-wave analyses. While the latest partial-wave analyses were found to fit the data reasonably well, all except one of the various model predictions not only do not fit the data well, but also tend to be in disagreement with each other. The data show no clear sign of a need for proposed dibaryon resonances.

9 data tables

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Measurements of $p p \to \pi^+ d$ between 398-MeV and 572-MeV

Aebischer, D. ; Favier, B. ; Greeniaus, L.G. ; et al.
Nucl.Phys.B 108 (1976) 214-238, 1976.
Inspire Record 114332 DOI 10.17182/hepdata.35777

The reaction pp→ π + d was studied at incident proton energies of 398, 455, 497, 530 and 572 MeV. Measurements of dσ/dΩ at 455 and 572 MeV show the presence of pion d-waves in the pion-deuteron system. Asymmetry measurements yield similar conclusions. Total cross-section measurements agree with recent fits to earlier data.

5 data tables

NORMALIZED TO 4.38 MB/SR AT THETA = 13.19 DEG FOR P P ELASTIC.

NORMALIZED TO 4.68 MB/SR AT THETA = 13.35 DEG FOR P P ELASTIC.

NORMALIZED (RELATIVE ERROR 2.1 PCT) TO THE DATA OF RICHARD-SERRE ET AL., NP B20, 413 (1970) (ABSOLUTE SCALE UNCERTAINTY 4.5 PCT).

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The reaction p p ---> pi+ d between 1.0 and 1.5 gev/c

Albrow, M.G. ; Andersson-Almehed, S. ; Bosnjakovic, B. ; et al.
Phys.Lett.B 34 (1971) 337-342, 1971.
Inspire Record 69312 DOI 10.17182/hepdata.28688

Polarizationdata for the reaction pp → π + d on polarized protons at 1.04, 1.13, 1.21, 1.37 and 1.45 GeV/ c are presented. The coefficient characterizing the angular distribution of the polarization show an energy dependence similar to that of the total cross-section and are consistent with the view that N ∗ ( 3 2 , 3 2 ) production dominates the reaction mechanism.

5 data tables

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Energy Dependence of the $P P \to \pi^+ D$ Differential Cross-section Between 500-{MeV} and 600-{MeV}

Hoftiezer, J. ; Weddigen, C. ; Favier, B. ; et al.
Phys.Lett.B 100 (1981) 462-465, 1981.
Inspire Record 170182 DOI 10.17182/hepdata.31203

The unpolarized differential cross section for the reaction pp→π + d has been measured at SIN at seven energies between 514 and 583 MeV. Data are presented in terms of a Legendre polynomial expansion. An observed strong energy dependence of the 4th order coefficient can be understood as a threshold phenomenon in a phenomenological NΔ resonant description. No evidence was found for a 1 D 2 dibaryon resonance near 600 MeV.

2 data tables

LEGENDRE POLYNOMIAL EXPANSION COEFFICIENTS DEFINED BY 4*PI*D(SIG)/DOMEGA = LEG(L=0)*P0 + LEG(L=2)*P2 + LEG(L=4)*P4. THUS, LEG(L=0) IS INTEGRATED CROSS SECTION SIG.

COEFFICIENTS OF COS(THETA)**2 EXPANSION OF 32*PI*D(SIG)/DOMEGA.


Strong Energy Dependence of the Analyzing Power in the $p p \to d \pi^+$ Reaction and the Question of an Isovector Dibaryon Resonance. 2.

Bertini, R. ; Roy, G. ; Durand, J.M. ; et al.
Phys.Lett.B 203 (1988) 18-21, 1988.
Inspire Record 247925 DOI 10.17182/hepdata.29981

Forward angular distributions of the analysing power for the pp→d π + reaction have been measured at six energies T p =1.2, 1.4, 1.6, 1.8, 2.0, 2.3 GeV. A strong energy dependence is observed for A y 0 ( t =0) and A y 0 ( θ CM π =90°). The data are compared with the backward angular distributions previously published and suggest the existence of a resonant state in the pp system at the approximate energy of 2.7 GeV.

6 data tables

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Energy dependence of the analyzing power for the p p ---> pi+ d reaction in the energy region 500-MeV - 800-MeV

Yoshida, H.Y. ; Shimizu, H. ; Ohnuma, H. ; et al.
Nucl.Phys.A 541 (1992) 443-452, 1992.
Inspire Record 320645 DOI 10.17182/hepdata.36702

The energy dependence of the analyzing power A y for the pp → π + d reaction was measured during polarized beam acceleration from 500 to 800 MeV, using an internal target inserted into the beam every acceleration cycle. The measurements were made with the pion laboratory angle fixed at 68° and with incident proton energy bins varying from 10 to 30 MeV in width. The statistical accuracy per bin is ΔA y ⋍ 0.06 .

1 data table

Statistical errors onnly.


ANALYZING POWER IN THE REACTION P P ---> D PI+ FOR BEAM MOMENTA FROM 1.17-GEV/C TO 1.96-GEV/C

Corcoran, M.d. ; Calkin, M.m. ; Hoftiezer, J.h. ; et al.
Phys.Lett.B 120 (1983) 309-313, 1983.
Inspire Record 190882 DOI 10.17182/hepdata.30825

The analyzing power A y 0 in the reaction p↑p→dπ + has been measured using the polarized proton beam at Argonne National Laboratory's zero gradient synchrotron. Data were taken at beam momenta of 1.17, 1.47, 1.70, and 1.96 GeV/ c and for pion center of mass angles from 8° to 163°.

1 data table

No description provided.


ANALYZING POWER FOR THE P (polarized) P ---> D PI+ REACTION AT 0.8-GEV AND EFFECTS OF DIBARYON ADMIXTURES

Seth, K.k. ; Saha, A. ; Kielczewska, D. ; et al.
Phys.Lett.B 126 (1983) 164-168, 1983.
Inspire Record 194165 DOI 10.17182/hepdata.30706

A precision measurement of the angular distribution of the analyzing power of the reaction p + p → d + π + has been made at 0.8 GeV. It is shown that none of the existing theoretical calculations, including those which introduce resonant dibaryon amplitudes, reproduce even the qualitative features of the data. It is concluded that our data do not require dibaryon admixtures of the kind proposed for the interpretation of recent data on vector analyzing power, i T 11 (θ), of π− d elastic scattering at the same center of mass energy.

5 data tables

LOWER ENERGY DATA NOT IN PUBLICATION.

LOWER ENERGY DATA NOT IN PUBLICATION.

LOWER ENERGY DATA NOT IN PUBLICATION.

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A STRONG ENERGY DEPENDENCE OF THE ANALYZING POWER IN THE P P ---> D PI+ REACTION AND THE QUESTION OF AN ISOVECTOR DIBARYON RESONANCE

Bertini, R. ; Arvieux, J. ; Boivin, M. ; et al.
Phys.Lett.B 162 (1985) 77-80, 1985.
Inspire Record 221962 DOI 10.17182/hepdata.30330

The angular distributions of the analyzing power for the pp → dπ + reaction have been measured at seven energies T p = 1.2, 1.4, 1.6, 1.7, 1.8, 2.0 and 2.3 GeV. The data show a strong energy dependence with a structure centered at √ s π d = 2.66 GeV. Possible interpretations are presented in the frame of the OPE model and involving the question of the excitation of a dibaryon resonance.

7 data tables

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