Analyzing power in pion-proton bremsstrahlung, and the. Delta. sup ++ (1232) magnetic moment

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.44.1962· OSTI ID:5101242

Bosshard, A; Amsler, C; Doebeli, M; Doser, M; Schaad, M; Riedlberger, J; Truoel, P ^[1]; Bistirlich, J A; Crowe, K M; Ljungfelt, S; Meyer, C A ^[2]; van den Brandt, B; Konter, J A; Mango, S; Renker, D ^[3]; Loude, J F; Perroud, J P ^[4]; Haddock, R P ^[5]; Sober, D I ^[6]

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1. Physik-Institut der Universitaet Zuerich, CH-8001 Zuerich (Switzerland)
2. Lawrence Berkeley Laboratory, University of California, Berkeley, California (USA)
3. Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)
4. Institut de Physique Nucleaire, Universite de Lausanne, CH-1015 Lausanne (Switzerland)
5. Physics Department, University of California, Los Angeles, California (USA)
6. Physics Department, Catholic University of America, Washington, D.C. (USA)

We report on a first measurement of the polarized-target asymmetry of the pion-proton bremsstrahlung cross section ({pi}{sup +}{ital p}{r arrow}{pi}{sup {minus}}{ital p}{gamma}). As in previous cross section measurements the pion energy (298 MeV) and the detector geometry for this experiment was chosen to optimize the sensitivity to the radiation from the magnetic dipole moment of the {Delta}{sup ++}(1232) resonance {mu}{sub {Delta}}. Comparison to a recent isobar model for pion-nucleon bremsstrahlung yields {mu}{sub {Delta}}=(1.62{plus minus}0.18){mu}{sub {ital p}}, where {mu}{sub {ital p}} is the proton magnetic moment. Since the asymmetry depends less than the cross section on the choice of the other input parameters for the model, their uncertainties affect this analysis by less than the experimental error. However the theory fails to represent both the cross section and the asymmetry data at the highest photon energies. Hence further improvements in the calculations are needed before the model dependence of the magnetic moment analysis can be fully assessed. The present result agrees with bag-model corrections to the SU(6) prediction {mu}{sub {Delta}}=2{mu}{sub {ital p}}. As a by-product, the analyzing power for elastic {pi}{sup +}{ital p} scattering at 415 MeV/{ital c} was also measured. This second result is in good agreement with phase shift calculations.

• DOE Contract Number: AT03-81ER40006
• OSTI ID: 5101242
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 44:7; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

645103* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Strong Interactions & Baryon & Meson Properties
645204 -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Strong Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANALYZING POWER
BAG MODEL
BARYONS
BREMSSTRAHLUNG
COMPOSITE MODELS
CROSS SECTIONS
DELTA BARYONS
DELTA-1232 BARYONS
ELASTIC SCATTERING
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
EXTENDED PARTICLE MODEL
FERMIONS
HADRON-HADRON INTERACTIONS
HADRONS
INTERACTIONS
MAGNETIC MOMENTS
MATHEMATICAL MODELS
MESON-BARYON INTERACTIONS
MESON-NUCLEON INTERACTIONS
MEV RANGE
MEV RANGE 100-1000
N BARYONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PCAC THEORY
PION PLUS-PROTON INTERACTIONS
PION-NUCLEON INTERACTIONS
PION-PROTON INTERACTIONS
POLARIZED TARGETS
QUARK MODEL
QUASI PARTICLES
RADIATIONS
SCATTERING
TARGETS