Observation of an ''ABC'' Effect in Proton-Proton Collisions

Journal Article · Fri May 15 04:00:00 EDT 2009 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.102.192301· OSTI ID:21316707

Dymov, S; Yaschenko, S ^[1]; Hartmann, M; Kacharava, A; Nekipelov, M; Ohm, H; Rathmann, F; Stroeher, H ^[2]; Khoukaz, A; Mielke, M ^[3]; Komarov, V; Kulikov, A; Kurbatov, V; Uzikov, Yu; Zalikhanov, B ^[1]; Kulessa, P ^[4]; Macharashvili, G ^[1]; Merzliakov, S; Tsirkov, D ^[1]; Mikirtychiants, S ^[2]

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1. Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation)
2. Institut fuer Kernphysik, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany)
3. Institut fuer Kernphysik, Universitaet Muenster, D-48149 Muenster (Germany)
4. H. Niewodniczanski Institute of Nuclear Physics PAN, PL-31342 Krakow (Poland)

The cross section for inclusive multipion production in the pp{yields}ppX reaction was measured at COSY-ANKE at four beam energies, 0.8, 1.1, 1.4, and 2.0 GeV, for low excitation energy in the final pp system, such that the diproton quasiparticle is in the {sup 1}S{sub 0} state. At the three higher energies, the missing-mass M{sub X} spectra show a strong enhancement at low M{sub X}, corresponding to an Abashian-Booth-Crowe effect that moves steadily to larger values as the energy is increased. Despite the missing-mass structure looking very different at 0.8 GeV, the variation with M{sub X} and beam energy are consistent with two-pion production being mediated through the excitation of two {delta}(1232) isobars, coupled to S and D states of the initial pp system. There is no sign of any resonancelike structure in the energy dependence of the type recently observed for the pn{yields}d{pi}{sup 0}{pi}{sup 0} total cross section.

• OSTI ID: 21316707
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 102; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABC EFFECT
COSY STORAGE RING
D STATES
DELTA-1232 BARYONS
ENERGY DEPENDENCE
EXCITATION
GEV RANGE 01-10
MISSING MASS
PARTICLE PRODUCTION
PROTON-PROTON INTERACTIONS
TOTAL CROSS SECTIONS