• Media type: E-Article
  • Title: Two-pion production in proton-proton collisions with a polarized beam
  • Contributor: Abd El-Bary, S. [Author]; COSY-TOF, Collab. [Author]
  • imprint: Springer, 2008
  • Published in: The European physical journal / A 37, 267 - 277 (2008). doi:10.1140/epja/i2008-10637-y
  • Language: English
  • DOI: https://doi.org/10.1140/epja/i2008-10637-y
  • ISSN: 1434-6001
  • Keywords: p: polarized beam ; 0.75: 0.80 GeV-cms-kin ; pi: pair production ; p p --> 2p pi+ pi- ; spectrometer: time-of-flight ; Juelich COSY PS ; p p: exclusive reaction ; cross section: energy dependence ; angular distribution ; analyzing power: vector ; N(1440) ; experimental results
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  • Description: The two-pion production reaction pp -> pp pi(+)pi(-) was measured with a polarized proton beam at T-p approximate to 750 and 800MeV using the short version of the COSY-TOF spectrometer. The implementation of a delayed-pulse technique for Quirl and central calorimeter provided positive pi(+) identification in addition to the standard particle identification, energy determination as well as time-of-flight and angle measurements. Thus all four-momenta of the emerging particles could be determined with 1-4 overconstraints. Total and differential cross-sections as well as angular distributions of the vector analyzing power have been obtained. They are compared to previous data and theoretical calculations. In contrast to predictions we find significant analyzing-power values up to A(y) = 0.3. The data taken in the energy region of the excitation of the Roper resonance confirm that its dominant pi pi decay channel is N* -> N sigma.
  • Access State: Open Access