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The European Physical Journal A

, Volume 35, Issue 3, pp 317–319 | Cite as

Excitation of the Roper resonance in single- and double-pion production in nucleon-nucleon collisions

  • The CELSIUS-WASA Collaboration
  • T. Skorodko
  • M. Bashkanov
  • D. Bogoslawsky
  • H. Calen
  • F. Cappellaro
  • H. ClementEmail author
  • L. Demiroers
  • E. Doroshkevich
  • D. Duniec
  • C. Ekström
  • K. Franssen
  • L. Gustafsson
  • B. Höistad
  • G. Ivanov
  • M. Jacewicz
  • E. Jiganov
  • T. Johansson
  • O. Khakimova
  • M. Kaskulov
  • S. Keleta
  • I. Koch
  • F. Kren
  • S. Kullander
  • A. Kupść
  • A. Kuznetsov
  • P. Marciniewski
  • R. Meier
  • B. Morosov
  • C. Pauly
  • H. Petterson
  • Y. Petukhov
  • A. Povtorejko
  • K. Schönning
  • W. Scobel
  • B. Shwartz
  • V. Sopov
  • J. Stepeniak
  • P. Thörngren-Engblom
  • V. Tikhomirov
  • G. J. Wagner
  • M. Wolke
  • A. Yamamoto
  • J. Zabierowski
  • J. Złomanczuk
Regular Article - Experimental Physics

Abstract.

In most investigations the Roper resonance is sensed only very indirectly via complex partial-wave analyses. We find indications for its excitation in the invariant nπ+ mass spectrum of the ppnpπ+ reaction at M ≈ 1360 MeV with a width of ≈ 150 MeV . The values fit very favorably to the most recent phase shift results as well as to the observations at BES. In the near-threshold two-pion production ppppπ0π0 , where the Roper excitation and its subsequent decays via the routes N * → Δπ → Nππ and N *Nσ are the only dominant processes, we find its direct decay into the Nσ channel to be the by far dominating decay process --in favor of a monopole excitation of the Roper resonance.

PACS.

13.75.Cs Nucleon-nucleon interactions (including antinucleons, deuterons, etc.) 14.20.Gk Baryon resonances with S = 0  

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Copyright information

© Società Italiana di Fisica and Springer-Verlag 2008

Authors and Affiliations

  • The CELSIUS-WASA Collaboration
  • T. Skorodko
    • 1
  • M. Bashkanov
    • 1
  • D. Bogoslawsky
    • 2
  • H. Calen
    • 3
  • F. Cappellaro
    • 4
  • H. Clement
    • 1
    Email author
  • L. Demiroers
    • 5
  • E. Doroshkevich
    • 1
  • D. Duniec
    • 4
  • C. Ekström
    • 3
  • K. Franssen
    • 3
  • L. Gustafsson
    • 4
  • B. Höistad
    • 4
  • G. Ivanov
    • 2
  • M. Jacewicz
    • 4
  • E. Jiganov
    • 2
  • T. Johansson
    • 4
  • O. Khakimova
    • 1
  • M. Kaskulov
    • 1
  • S. Keleta
    • 1
  • I. Koch
    • 4
  • F. Kren
    • 1
  • S. Kullander
    • 4
  • A. Kupść
    • 3
  • A. Kuznetsov
    • 2
  • P. Marciniewski
    • 3
  • R. Meier
    • 1
  • B. Morosov
    • 2
  • C. Pauly
    • 5
  • H. Petterson
    • 4
  • Y. Petukhov
    • 2
  • A. Povtorejko
    • 2
  • K. Schönning
    • 4
  • W. Scobel
    • 5
  • B. Shwartz
    • 6
  • V. Sopov
    • 7
  • J. Stepeniak
    • 8
  • P. Thörngren-Engblom
    • 4
  • V. Tikhomirov
    • 2
  • G. J. Wagner
    • 1
  • M. Wolke
    • 9
  • A. Yamamoto
    • 10
  • J. Zabierowski
    • 11
  • J. Złomanczuk
    • 4
  1. 1.Physikalisches Institut der Universität TübingenTübingenGermany
  2. 2.Joint Institute for Nuclear ResearchDubnaRussia
  3. 3.The Svedberg LaboratoryUppsalaSweden
  4. 4.Uppsala UniversityUppsalaSweden
  5. 5.Hamburg UniversityHamburgGermany
  6. 6.Budker Institute of Nuclear PhysicsNovosibirskRussia
  7. 7.Institute of Theoretical and Experimental PhysicsMoscowRussia
  8. 8.Soltan Institute of Nuclear StudiesWarsawPoland
  9. 9.Forschungszentrum JülichGermany
  10. 10.High Energy Accelerator Research OrganizationTsukubaJapan
  11. 11.Soltan Institute of Nuclear StudiesLodzPoland

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