Diagrammatic Approach to Meson Production in Proton-Proton Collisions near Threshold

Conference · Sun Dec 31 04:00:00 EST 2000

OSTI ID:784258

Kaiser, Norbert

We evaluate the threshold T-matrices for the reactions pp {yields} pp{pi}{sup 0}, pn{pi}{sup +}, pp{eta}, pp{omega},p{Lambda}K{sup +}, and pn {yields} pn{eta} in a relativistic Feynman diagram approach. We employ an effective range approximation to take care of the strong S-wave pN and p{Lambda} final-state interaction. We stress that the heavy baryon formalism is not applicable in the NN-system above {pi}-production threshold due to the large external momentum, {vert_bar}{rvec p}{vert_bar} {approx_equal} {radical}(Mm{sub {pi}}). The magnitudes of the experimental threshold amplitudes extracted from total cross section data, script-A = (2.7{minus}0.3i)fm{sup 4}, script-B = (2.8{minus}1.5i)fm{sup 4}, {vert_bar}script-C{vert_bar} = 1.32 fm{sup 4}, {vert_bar}{Omega}{vert_bar} = 0.53 fm{sup 4}, script-K = {radical}(2{vert_bar}K{sub s}{vert_bar}{sup 2} + {vert_bar}K{sub t}{vert_bar}{sup 2}) = 0.38 fm{sup 4} and {vert_bar}script-D{vert_bar} = 2.3 fm{sup 4} can be reproduced by (long-range) o ne-pion exchange and short-range vector meson exchanges, with the latter giving the largest contributions. Pion loop effects in pp {yields} pp{pi}{sup 0} appear to be small. The presented diagrammatic approach requires further tests via studies of angular distributions and polarization observables.

• Research Organization: TU Muenchen, Physik Dept., Garching (DE)
• Sponsoring Organization: None (US)
• OSTI ID: 784258
• Report Number(s): NONE; ISBN 1-56396-928-9; ISSN 0094-243X; CODEN APCPCS; ISBN 1-56396-928-9; ISSN 0094-243X; CODEN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR DISTRIBUTION
BOSON EXCHANGE MODELS
EFFECTIVE RANGE THEORY
ETA MESONS
FEYNMAN DIAGRAM
FINAL-STATE INTERACTIONS
GEV RANGE 01-10
GOLDSTONE BOSONS
KAONS PLUS
LAMBDA BARYONS
LAMBDA PARTICLES
NEUTRONS
OMEGA-782 MESONS
OMETA-782 MESONS
PARTICLE PRODUCTION
PIONS NEUTRAL
PIONS PLUS
PROTON-NEUTRON INTERACTIONS
PROTON-PROTON INTERACTIONS
PROTONS
S MATRIX
SCATTERING AMPLITUDES
TOTAL CROSS SECTIONS