Exclusive Measurement of the $pp \to nn\pi^+\pi^+$ Reaction at 1.1 GeV

The CELSIUS/WASA collaboration Skorodko, T. ; Bashkanov, M. ; Bogoslawsky, D. ; et al.
Eur.Phys.J.A 47 (2011) 108, 2011.
Inspire Record 879711 DOI 10.17182/hepdata.63827

First exclusive data for the $pp \to nn\pi^+\pi^+$ reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of $T_p$ = 1.1 GeV. Total and differential cross sections disagree with theoretical calculations, which predict the $\Delta\Delta$ excitation to be the dominant process at this beam energy. Instead the data require the excitation of a higher-lying $\Delta$ state, most likely the $\Delta(1600)$, to be the leading process.

9 data tables

Total cross section.

Distribution of the invariant mass of the PI+PI+ system.

Distribution of the cosine of the PI+_PI+ opening angle DELTA at an incident kinetic energy of 1.1 GeV.

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Cross section of the $pp\to K^+\Sigma^+n$ reaction close to threshold

The COSY-HIRES collaboration Budzanowski, A. ; Chatterjee, A. ; Clement, H. ; et al.
Phys.Lett.B 692 (2010) 10-14, 2010.
Inspire Record 861052 DOI 10.17182/hepdata.55371

We have measured inclusive data on $K^+$-meson production in $pp$ collisions at COSY J\"ulich close to the hyperon production threshold and determined the hyperon-nucleon invariant mass spectra. The spectra were decomposed into three parts: $\Lambda p$, $\Sigma^0p$ and $\Sigma^+n$. The cross section for the $\Sigma^+n$ channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence.

3 data tables

Total cross section for P P --> K+ SIGMA+ N. Errors are combined statistics and systematics.

Deduced total cross section for P P --> K+ P LAMBDA.

Deduced total cross section for P P --> K+ SIGMA0 P.


Differential cross sections for elastic pi+ p scattering between 1.2 and 2.3 GeV/c

Abe, K. ; Barnett, B.A. ; Goldman, J.H. ; et al.
Phys.Rev.D 10 (1974) 3556-3572, 1974.
Inspire Record 97248 DOI 10.17182/hepdata.238

Differential cross sections for π+p elastic scattering in the momentum region 1.2 to 2.3 GeV/c are presented for the center-of-mass angular range 0.9>cosθ>−0.9. Typically, 50 000 events were obtained at each of 16 momenta using magnetostrictive-readout wire spark chambers to detect the particles scattered from a liquid hydrogen target. The results are compared to those of the CERN-71 phase-shift analysis. The well-known dips at t≅−0.7 (GeV/c)2 and at u′=−0.2 (GeV/c)2 are observed. In addition, structure is seen at constant u′=−1.3 (GeV/c)2. The results of a pion attenuation study in iron are also presented.

18 data tables

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