Isoscalar single-pion production in the region of Roper and d(2380) resonances

P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov*, F. S. Bergmann, M. Berłowski, H. Bhatt, A. Bondar, M. Büscher, H. Calén, I. Ciepał, H. Clement, E. Czerwiński, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. FöhlK. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, C. O. Gullström, L. Heijkenskjöld, V. Hejny, N. Hüsken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, D. A. Kirillov, S. Kistryn, H. Kleines, B. Kłos, W. Krzemień, P. Kulessa, A. Kupść, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Mariański, H. P. Morsch, P. Moskal, H. Ohm, W. Parol, E. Perez del Rio, N. M. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schätti-Ozerianska, T. Sefzick, V. Serdyuk, B. Shwartz, K. Sitterberg, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, E. Stephan, G. Sterzenbach, H. Stockhorst, H. Ströher, A. Szczurek, A. Trzciński, R. Varma, M. Wolke, A. Wrońska, P. Wüstner, A. Yamamoto, J. Zabierowski, M. J. Zieliński, J. Złomańczuk, P. Żuprański, M. Żurek

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Exclusive measurements of the quasi-free pn→ppπ and pp→ppπ0 reactions have been performed by means of pd collisions at Tp=1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region Tp=0.95–1.3 GeV (s=2.3–2.46 GeV), which includes the regions of Δ(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 Tp=1 GeV. We observe a substantial increase of this cross section around 1 GeV, which can be related to the Roper resonance N(1440), the strength of which shows up isolated from the Δ resonance in the isoscalar (Nπ)I=0 invariant-mass spectrum. No evidence for a decay of the dibaryon resonance d(2380) into the isoscalar (NNπ)I=0 channel is found. An upper limit of 180 μb (90% C.L.) corresponding to a branching ratio of 9% has been deduced.

Original languageEnglish
Pages (from-to)599-607
Number of pages9
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number599
Early online date10 Oct 2017
Publication statusPublished - 10 Nov 2017

Bibliographical note

© 2017 The Author(s). Published by Elsevier B.V.


  • Dibaryon resonance
  • Isoscalar part
  • Roper resonance
  • Single-pion production

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