Systematic Study of Two-Pion Production in NN Collisions--from Single-Baryon to Di-Baryon Excitations

Journal Article · Thu Aug 05 04:00:00 EDT 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3483384· OSTI ID:21426447

Skorodko, T; Bashkanov, M; Clement, H; Doroshkevich, E; Khakimova, O; Kren, F; Pricking, A; Wagner, G J ^[1]

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1. Physikalisches Institut der Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

The two-pion production in nucleon-nucleon collisions has been studied by exclusive and kinematically complete experiments from threshold up to T{sub p} = 1.36 GeV at CELSIUS-WASA. At near-threshold energies the total and differential distributions for the {pi}{sup +{pi}-} and {pi}{sup 0{pi}0} channels are dominated by Roper excitation and its decay into N{sigma}s and {Delta}{pi} channels. At beam energies T{sub p}>1.1 GeV the {Delta}{Delta} excitation governs the two-pion production process. In the {pi}{sup +{pi}+} channel evidence is found for the excitation of a higher-lying I =3/2 resonance, favorably the {Delta}(1600). The isovector fusion processes leading to the deuteron and to quasi-stable {sup 2}He, respectively, exhibit no or only a modest ABC-effect, i.e. low-mass enhancement in the {pi}{pi}-invariant mass spectrum, and can be described by conventional t-channel {Delta}{Delta} excitation. On the other hand, the isoscalar fusion process to the deuteron exhibits a dramatic ABC-effect correlated with a narrow resonance-like energy dependence in the total cross section with a width of only 50 MeV and situated at a mass 90 MeV below the {Delta}{Delta} mass.

• OSTI ID: 21426447
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1257; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABC EFFECT
BARYON-BARYON INTERACTIONS
BARYONS
BOSONS
CHARGED PARTICLES
COMPOSITE MODELS
CROSS SECTIONS
DECAY
DELTA BARYONS
DEUTERONS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
FERMIONS
GEV RANGE
HADRON-HADRON INTERACTIONS
HADRONS
INTERACTIONS
MASS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MESON-MESON INTERACTIONS
MESONS
MEV RANGE
MULTIPARTICLE SPECTROMETERS
N*BARYONS
NUCLEON-NUCLEON INTERACTIONS
PARTICLE DECAY
PARTICLE IDENTIFICATION
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PION-PION INTERACTIONS
PIONS
PIONS MINUS
PIONS PLUS
PSEUDOSCALAR MESONS
QUARK MODEL
REST MASS
SPECTROMETERS
T CHANNEL
TOTAL CROSS SECTIONS