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

P. Adlarsona, W. Augustyniak, W. Bardan, M. Bashkanov, F. S. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buescher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. FoehlK. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, C. -O. Gullstrom, L. Heijkenskjoeld, V. Hejny, N. Huesken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, D. A. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, WASA-at-COSY Collaboration

Research output: Contribution to journalArticlepeer-review


Exclusive measurements of the quasi-free pn -> pp pi(-) and pp -> 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 (root s = 2.3-2.46 GeV), which includes the regions of triangle(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 around 1 GeV, which can be related to the Roper resonance N*(1440), the strength of which shows up isolated from the triangle 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% CL.) corresponding to a branching ratio of 9% has been deduced.

Original languageEnglish
Pages (from-to)599-607
Number of pages9
JournalPhysics Letters B
Early online date10 Nov 2017
Publication statusPublished - 10 Nov 2017


  • Single-pion production
  • Isoscalar part
  • Roper resonance
  • Dibaryon resonance
  • GEV/C

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