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Kullander, Sven
Publications (10 of 21) Show all publications
Skorodko, T., Bashkanov, M., Bogoslawsky, D., Calén, H., Clement, H., Doroshkevich, E., . . . Zlomanczuk, J. (2011). Exclusive measurement of the pp -> nn pi(+)pi(+) reaction at 1.1 GeV. European Physical Journal A, 47(9), 108
Open this publication in new window or tab >>Exclusive measurement of the pp -> nn pi(+)pi(+) reaction at 1.1 GeV
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2011 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 47, no 9, p. 108-Article in journal (Refereed) Published
Abstract [en]

First exclusive data for the pp -> nnp(+)pi(+) reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of T(p) - 1.1 GeV. Total and differential cross-sections disagree with theoretical calculations, which predict the Delta Delta excitation to be the dominant process at this beam energy. Instead, the data require the excitation of one of the nucleons to a higher-lying Delta state, preferably the Delta(1600)P(33), to be the leading process.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-162716 (URN)10.1140/epja/i2011-11108-2 (DOI)000296632400009 ()
Available from: 2011-12-05 Created: 2011-12-05 Last updated: 2017-12-08Bibliographically approved
Skorodko, T., Bashkanov, M., Bogoslawsky, D., Calèn, H., Clement, H., Doroshkevich, E., . . . Zlomanczuk, J. (2009). Two-pion production in proton-proton collisions: experimental total cross sections and their isospin decomposition. Physics Letters B, 679(1), 30-35
Open this publication in new window or tab >>Two-pion production in proton-proton collisions: experimental total cross sections and their isospin decomposition
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2009 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 679, no 1, p. 30-35Article in journal (Refereed) Published
Abstract [en]

The two-pion production in pp-collisions has been investigated at CELSIUS in exclusive measurements from threshold up to T-P = 1.36 GeV. Total and differential Cross sections have been obtained for the channels pn pi(+)pi(0), pp pi(+)pi(-), pp pi(0)pi(0) and also nn pi(+)pi(+). For intermediate incident energies T-P > 1GeV, i.e. in the region which is beyond the Roper excitation but at the onset of Delta Delta excitation, the total pp pi(0)pi(0) cross section falls behind theoretical predictions by as much as all order of magnitude near 1.2 GeV, whereas the nn pi(+)pi(+) cross section is a factor of five larger than predicted. An isospin decomposition of the total cross sections exhibits a s-channel-like energy dependence in the region of the Roper excitation as well as a significant contribution of an isospin 3/2 resonance other than the Delta(1232). As possible candidates the Delta(1600) and the Delta(1700) are discussed. (C) 2009 Elsevier B.V. All rights reserved.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-128282 (URN)10.1016/j.physletb.2009.07.012 (DOI)000269299900007 ()
Available from: 2010-07-21 Created: 2010-07-20 Last updated: 2017-12-12Bibliographically approved
Bargholtz, C., Bashkanov, M., Berlowski, M., Bondar, A., Bogoslawsky, D., Brodowski, W., . . . Zlomanczuk, J. (2008). The WASA detector facility at CELSIUS. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 594(3), 339-350
Open this publication in new window or tab >>The WASA detector facility at CELSIUS
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2008 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 594, no 3, p. 339-350Article in journal (Refereed) Published
Abstract [en]

The WASA 4 pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A unique feature of the system is the use of hydrogen pellets as internal targets for the first time. A detailed description of the design, together with the anticipated and achieved performance parameters are given. (C) 2008 Elsevier B.V. All rights reserved.

Keywords
multidetector system, pellet target, calorimeter, mini drift chambers, scintillators
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-107849 (URN)10.1016/j.nima.2008.06.011 (DOI)000259848900004 ()
Available from: 2009-09-02 Created: 2009-08-31 Last updated: 2017-12-13Bibliographically approved
Bashkanov, M., Calèn, H., Cappellaro, F., Ekström, C., Fransson, K., Gustafsson, L., . . . Zlomanczuk, J. (2007). Low-mass pi pi enhancement in baryonic pi pi production: ABC effect revised by exclusive measurements. International Journal of Modern Physics A, 22(2-3), 625-628
Open this publication in new window or tab >>Low-mass pi pi enhancement in baryonic pi pi production: ABC effect revised by exclusive measurements
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2007 (English)In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 22, no 2-3, p. 625-628Article in journal (Refereed) Published
Abstract [en]

The ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of double-pionic fusion to nuclear bound states - has been investigated since 40 years by inclusive measurements without providing a conclusive interpretation. First exclusive measurements to this topic have now been carried out at CELSIUS-WASA. They confirm a huge ππ threshold enhancement, prove it to be of scalar-isoscalar nature, i.e., a σ-channel phenomenon and reveal the theoretically predicted high-mass enhancement in inclusive spectra to be of πππ rather than of ππ nature - falsifying thus corresponding model predictions for the ABC effect. From the kinematically complete data samples we infer that the interaction between the two Δ particles created in this process is of crucial importance.

Keywords
ABC effect, σ channel enhancement, ∆∆ interaction, medium effects
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16890 (URN)10.1142/S0217751X07035987 (DOI)000250926800065 ()
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
Bashkanov, M., Bogoslawsky, D., Calén, H., Capellaro, F., Clement, H., Demirörs, L., . . . Zlomanczuk, J. (2007). Measurement of the slope parameter for the η → 3π0 decay in the pp → ppη reaction. Physical Review C. Nuclear Physics, 76(4), 048201
Open this publication in new window or tab >>Measurement of the slope parameter for the η → 3π0 decay in the pp → ppη reaction
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2007 (English)In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 4, p. 048201-Article in journal (Refereed) Published
Abstract [en]

The CELSIUS-WASA setup is used to measure the 3π0 decay of η mesons produced in pp interactions with beam kinetic energies of 1.36 and 1.45 GeV. The efficiency-corrected Dalitz plot and density distributions for this decay are shown, together with a fit of the quadratic slope parameter α yielding α = −0.026 ± 0.010(stat) ± 0.010(syst). This value is compared to recent experimental results and theoretical predictions.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16829 (URN)10.1103/PhysRevC.76.048201 (DOI)000250620900091 ()
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
Khakimova, O., Calèn, H., Cappellaro, F., Ekström, C., Fransson, K., Gustafsson, L., . . . Zlomanczuk, J. (2007). Observation of the abc effect in the first exclusive measurements of pn -> d pi(0)pi(0). International Journal of Modern Physics A, 22(2-3), 617-620
Open this publication in new window or tab >>Observation of the abc effect in the first exclusive measurements of pn -> d pi(0)pi(0)
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2007 (English)In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 22, no 2-3, p. 617-620Article in journal (Refereed) Published
Abstract [en]

The reaction pn → dπ0π0 constitutes the most fundamental system for the study of the ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of the ππ system in double-pionic fusion to nuclear bound states. The first exclusive measurements of this reaction have now been carried out at CELSIUS-WASA. They exhibit a striking low-mass enhancement in the ππ invariant mass spectrum, prove it to be a σ-channel phenomenon and falsify conventional theoretical models, which predict an associated high-mass enhancement not present in the new exclusive data. In the kinematically complete data sample we observe a ΔΔ excitation, where the interaction between the two Δ obviously plays a crucial role for the generation of the ππ low-mass enhancement.

Keywords
ABC effect, σ channel enhancement, ΔΔ interaction, medium effects
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16891 (URN)10.1142/S0217751X07035963 (DOI)000250926800063 ()
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
Skorodko, T., Calèn, H., Cappellaro, F., Ekström, C., Fransson, K., Greiff, J., . . . Zlomanczuk, J. (2007). pi pi production in proton-proton collisions. International Journal of Modern Physics A, 22(2-3), 509-513
Open this publication in new window or tab >>pi pi production in proton-proton collisions
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2007 (English)In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 22, no 2-3, p. 509-513Article in journal (Refereed) Published
Abstract [en]

At CELSIUS-WASA the two-pion production in proton-proton collisisons has been measured exclusively from threshold up to the energy regime, where both of the collision partners are expected to be excited to the Δ state. The measurements constitute the first kinematically complete data samples of solid statistics in this energy range. Most of the data have been obtained for the π+π- and π0π0channels. Whereas at near-threshold energies the differential distributions can be succesfully explained by chiral dynamics and Roper excitation, respectively, the data for the π+π- channel in the ΔΔ region can be described only, if the special configuration (ΔΔ)0+ is assumed. The data for the π0π0 channel moreover exhibit a low-mass enhancement in the π0π0 invariant mass spectrum, which is reminiscent of the ABC-effect found in double-pionic fusion to light nuclei.

Keywords
Roper excitation, ΔΔ excitation, σ channel enhancement, ABC effect, ππ interaction
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16892 (URN)10.1142/S0217751X07035720 (DOI)000250926800039 ()
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
Pauly, C., Jacewicz, M., Koch, I., Calen, H., Capellaro, F., Fransson, K., . . . Zlomanczuk, J. (2007). The p p -> p p pi pi pi reaction channels in the threshold region.
Open this publication in new window or tab >>The p p -> p p pi pi pi reaction channels in the threshold region
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2007 (English)Report (Other scientific)
Series
e-Print ; nucl-ex/0602006
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-22824 (URN)
Available from: 2007-01-22 Created: 2007-01-22
Pauly, C., Jacewicz, M., Koch, I., Bashkanov, M., Bogoslawsky, D., Calén, H., . . . Zlomanczuk, J. (2007). The pp→ppπππ reaction channels in the threshold region. Physics Letters B, 649(2-3), 122-127
Open this publication in new window or tab >>The ppppπππ reaction channels in the threshold region
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2007 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 649, no 2-3, p. 122-127Article in journal (Refereed) Published
Abstract [en]

The cross section for direct neutral and charged three pion production in pp interactions was measured at excess energies in the range 160–216 MeV. That comprises the first measurement of the ppppπ0π0π0 reaction and the direct comparison with the ppppπ+ππ0 process. The experiment was performed above the η meson production threshold and the cross section could be directly normalized to the cross section of the ppppη reaction, with the η decaying into 3 pions. Since the same final states are selected, the measurement has a low systematical error. The measured cross section ratio σ(ppppπ+ππ0)/σ(ppppπ0π0π0) is compared to predictions of dominance of different isobars in the intermediate state.

Keywords
Threshold measurement, Three pion production, Final state interaction
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16830 (URN)10.1016/j.physletb.2007.04.004 (DOI)000247170700003 ()
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
Calen, H., Fransson, K., Gustafsson, L., Hoistad, B., Jacewicz, M., Johansson, T., . . . Zlomanczuk, J. (2006). Evidence for a 'Narrow' Roper Resonance - The Breathing Mode of the Nucleon.
Open this publication in new window or tab >>Evidence for a 'Narrow' Roper Resonance - The Breathing Mode of the Nucleon
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2006 (English)Report (Other scientific)
Series
e-Print arXiv ; nucl-ex/0612015
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-23534 (URN)
Available from: 2007-01-30 Created: 2007-01-30
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