Two-pion production in the {delta}{delta} region: Is the ABC-effect the result of a resonance in the pn{r_reversible}{delta}{delta} system?

Journal Article · Wed Nov 07 04:00:00 EST 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2819044· OSTI ID:21039258

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

---

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

The ABC effect--a puzzling low-mass enhancement in the {pi}{pi} invariant mass spectrum--is known from inclusive measurements of two-pion production in nuclear fusion reactions. Exclusive measurements conducted at CELSIUS-WASA for the fusion reactions leading to d and {sup 3}He in the final state reveal the ABC effect to be of scalar-isoscalar nature and to be associated with the formation of a resonance in the pn{r_reversible}{delta}{delta} systems in the intermediate state. The differential distributions for the {pi}{sup 0}{pi}{sup 0} channels can be well described, if a quasi-bound state within the {delta}{delta} system is assumed, which gives rise to a resonance structure in the total cross section. This ansatz is capable of describing all differential cross sections including the results of previous inclusive measurements on {sup 4}He as well as the energy dependence of the total cross sections.

• OSTI ID: 21039258
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 950; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABC EFFECT
BOUND STATE
DELTA BARYONS
DIFFERENTIAL CROSS SECTIONS
DISTRIBUTION
ENERGY DEPENDENCE
HELIUM 3
HELIUM 4
INTERMEDIATE STATE
MASS SPECTRA
NUCLEON-NUCLEON INTERACTIONS
PARTICLE PRODUCTION
PIONS NEUTRAL
RESONANCE PARTICLES
REST MASS
THERMONUCLEAR REACTIONS
TOTAL CROSS SECTIONS