Large {sigma} Channel Low-Mass Enhancement in Exclusively Measured Double Pionic Fusion to 3He

Journal Article · Tue Jul 11 04:00:00 EDT 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2220293· OSTI ID:20873338

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

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

The pd {yields} 3He {pi}0{pi}0 and pd {yields} 3He {pi}+{pi}- reactions have been measured exclusively at CELSIUS using the WASA 4{pi} detector with pellet target system. For the double-pionic fusion to 3He data have been taken at Tp = 0.893 GeV, where the maximum of the socalled ABC effect is expected. A very large low-mass enhancement is observed in the {pi}0{pi}0 invariant mass spectrum M{pi}0{pi}0, whereas only a moderate low-mass enhancement is seen in M{pi}+{pi}- raising thus the question of isospin invariance in this region. With both channels summed up the data agree well to previous inclusive measurements regarding the low-mass enhancement. However, they do not exhibit the high-mass enhancement seen in the inclusive measurements and predicted by theoretical calculations based on a {delta}{delta} process, which produces a double-hump structure in the M{pi}{pi} spectra.

• OSTI ID: 20873338
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 842; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABC EFFECT
CELSIUS STORAGE RING
FOUR-PI DETECTORS
GEV RANGE
HELIUM 3
ISOSPIN
MASS
MASS SPECTRA
MULTIPARTICLE SPECTROMETERS
PARTICLE IDENTIFICATION
PARTICLE PRODUCTION
PROTON-NEUTRON INTERACTIONS
PROTON-PROTON INTERACTIONS