This title appears in the Scientific Report : 2017 

Isoscalar Single-Pion Production in the Region of Roper and $d^*(2380)$ Resonances
WASA-at-COSY Collaboration
Adlarson, P. (Corresponding author) / Augustyniak, W. / Bardan, W. / Bashkanov, M. / Bergmann, F. S. / Berłowski, M. / Bondar, A. / Calen, H. / Ciepał, I. / Clement, H. / Czerwinski, E. / Demmich, K. / Engels, Ralf W. / Erven, A. / Erven, W. / Eyrich, W. / Fedorets, P. / Föhl, K. / Fransson, K. / Goldenbaum, F. / Grigoryev, A. Goswami K. / Gullström, C. -O. / Heijkenskjöld, L. / Hejny, V. / Hüsken, N. / Jarczyk, L. / Johansson, T. / Kamys, B. / Kemmerling, G. / Khatri, G. / Khoukaz, A. / Khreptak, O. / Kirillov, D. A. / Kistryn, S. / Kleines, Harald / Kłos, B. / Krzemien, W. / Kulessa, P. / Kuzmin, A. / Lalwani, K. / Lersch, D. / Lorentz, B. / Magiera, A. / Maier, R. / Marciniewski, P. / Marianski, B. / Morsch, H. -P. / Ohm, H. / Parol, W. / del Rio, E. Perez / Piskunov, N. M. / Prasuhn, D. / Pszczel, D. / Pysz, K. / Pyszniak, A. / Ritman, J. / Roy, A. / Rudy, Z. / Rundel, O. / Sawant, S. / Schadmand, S. / Schätti-Ozerianska, I. / Sefzick, T. / Serdyuk, V. / Shwartz, B. / Sitterberg, K. / Skorodko, T. / Skurzok, M. / Smyrski, J. / Sopov, V. / Stassen, R. / Stepaniak, J. / Stephan, E. / Sterzenbach, G. / Stockhorst, H. / Ströher, H. / Szczurek, A. / Trzcinski, A. / Varma, R. / Wronska, A. / Wüstner, P. / Yamamoto, A. / Zabierowski, J. / Zielinski, M. J. / Złomanczuk, J. / Zupranski, P. / Zurek, M. / Büscher, Markus / Moskal, P. / Wolke, M. / Kupsc, A.
IKP- Technische und Administrative Infrastruktur; IKP-TA
Kernphysikalische Großgeräte; IKP-4
Zentralinstitut für Elektronik; ZEA-2
Experimentelle Hadrondynamik; IKP-2
Experimentelle Hadronstruktur; IKP-1
2017
Preprint
Cosmic Matter in the Laboratory
OpenAccess
OpenAccess
Please use the identifier: http://hdl.handle.net/2128/15005 in citations.
Exclusive measurements of the quasi-free $pn \to pp\pi^-$ and $pp \to pp\pi^0$ reactions have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $T_p = 0.95 - 1.3$ GeV ($\sqrt s$ = 2.3 - 2.46 GeV), which includes the regions of $\Delta(1232)$, $N^*(1440)$ and $d^*(2380)$ resonance excitations. From these measurements the isoscalar single-pion production has been extracted, for which data existed so far only below $T_p$ = 1 GeV. We observe a substantial increase of this cross section above 1 GeV, which can be related to the Roper resonance $N^*(1440)$, the strength of which shows up isolated from the $\Delta$ resonance in the isoscalar $(N\pi)_{I=0}$ invariant-mass spectrum. No evidence for a decay of the dibaryon resonance $d^*(2380)$ into the isoscalar $(NN\pi)_{I=0}$ channel is found. An upper limit of 180 $\mu$b (90 $\%$ C.L.) corresponding to a branching ratio of 9 $\%$ has been deduced.