1. On the production of $ \pi^{+}_{}$ $ \pi^{+}_{}$ pairs in pp collisions at 0.8 GeV
- Author
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Abd El Samad, S., Bilger, R., Brinkmann, K. T. h., Clement, H., Dietrich, M., Doroshkevich, E., Dshemuchadse, S., Ehrhardt, K., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Geyer, R., Gillitzer, A., Hauffe, J., Hesselbarth, D., Jaekel, R., Jakob, B., Karsch, L., Kilian, K., Kress, J., Kuhlmann, E., Marcello, Simonetta, Marwinski, S., Meier, R., Möller, K., Morsch, H. P., Naumann, L., Ritman, J., Roderburg, E., Schönmeier, P., Schulte Wissermann, M., Schroeder, W., Stinzing, F., Sun, G. Y., Wächter, J., Wagner, G. J., Wagner, M., Weidlich, U., Wilms, A., Wirth, S., Zhang, G., and Zupranski, P.
- Subjects
Nuclear and High Energy Physics ,Particle physics ,pion production ,chiral dynamics ,effect [nucleon resonance] ,Juelich COSY PS ,Pi ,approx. 0.8 GeV-kin ,Incident energy ,ddc:530 ,Nuclear Experiment ,inelastic proton scattering ,Physics ,time-of-flight [spectrometer] ,energy dependence [channel cross section] ,pair production [pi+] ,Resonance excitation ,hadrons ,+2n+2pi%2B%22">p p --> 2n 2pi+ ,nucleon-nucleon interactions ,baryon resonances ,inelastic scattering [p p] ,Production (computer science) ,Beam energy ,Order of magnitude - Abstract
Data accumulated recently for the exclusive measurement of the $pp\to pp\pi^+\pi^-$ reaction at a beam energy of 0.793 GeV using the COSY-TOF spectrometer have been analyzed with respect to possible events from the $pp \to nn\pi^+\pi^+$ reaction channel. The latter is expected to be the only $\pi\pi$ production channel, which contains no major contributions from resonance excitation close to threshold and hence should be a good testing ground for chiral dynamics in the $\pi\pi$ production process. No single event has been found, which meets all conditions for being a candidate for the $pp \to nn \pi^+\pi^+$ reaction. This gives an upper limit for the cross section of 0.16 $\mu$b (90% C.L.), which is more than an order of magnitude smaller than the cross sections of the other two-pion production channels at the same incident energy.
- Published
- 2009
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