Measurement of the reaction K/sup +/n/sub up-arrow/. -->. K/sup +/. pi. /sup -/p at 5. 98 and 11. 85 GeV/c using a transversely polarized deuteron target

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.39.21· OSTI ID:6794521

de Lesquen, A; van Rossum, L; Svec, M; Babou, M; Bystricky, J; Cozzika, G; Dobrowolski, T; Ducros, Y; Fujisaki, M; Gaidot, A; others, and

In an experiment carried out at the CERN Proton Synchrotron and using the CERN polarized deuteron target, the reaction K/sup +/n/sub up-arrow/..-->..K/sup +/..pi../sup -/p was measured in the region -t = 0.1--1.0 (GeV/c)/sup 2/ and m(K/sup +/..pi../sup -/) = 0.812--0.972 GeV at incident momenta of 5.98 and 11.8 GeV/c. The experiment yields the m and t dependence of 14 linearly independent spin-density-matrix elements describing the coherent production of K/sup +/..pi../sup -/ states with dimeson spins J = 0 and J = 1. This first measurement of the KN..-->..K..pi..N reaction on a polarized target enables us to study experimentally pion production on the level of production amplitudes. Although the mass dependence of partial cross sections averaged over nucleon spins is smooth, we observe large and systematic structures in the moduli squared of individual nucleon transversity amplitudes which reveal an unexpected but essential role of nucleon spin in the pion production process. Our polarization data suggest the possibility of a new state I = (1/2 0/sup ++/(860) with a width of 20--40 MeV. At present we consider this conclusion as only tentative. The predictions of the additive quark model relating K/sup +/n/sub up-arrow/..-->..K/sup *//sup 0/p and p/sub up-arrow/p..--> delta../sup ++/n are well satisfied at 6 GeV/c. Our results emphasize the need for a systematic study of single-pion production in a new generation of dedicated experiments with spin at the recently proposed high-intensity hadron facilities.

• Research Organization: Departement de Physique des Particules Elementaires, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette, France
• OSTI ID: 6794521
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 39:1; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645103* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Strong Interactions & Baryon & Meson Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
BARYONS
BOSONS
COHERENT PRODUCTION
COMPOSITE MODELS
DENSITY MATRIX
DEUTERIUM TARGET
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GEV RANGE
GEV RANGE 01-10
GEV RANGE 10-100
HADRON-HADRON INTERACTIONS
HADRONS
HELICITY
INTERACTIONS
KAON PLUS-NEUTRON INTERACTIONS
KAON-NEUTRON INTERACTIONS
KAON-NUCLEON INTERACTIONS
KAONS
KAONS PLUS
MATHEMATICAL MODELS
MATRICES
MATRIX ELEMENTS
MESON-BARYON INTERACTIONS
MESON-NUCLEON INTERACTIONS
MESONS
NUCLEONS
P WAVES
PARTIAL WAVES
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
PHASE SHIFT
PIONS
PIONS MINUS
POLARIZED TARGETS
PROTONS
PSEUDOSCALAR MESONS
QUARK MODEL
S WAVES
SPIN
STRANGE MESONS
STRANGE PARTICLES
TARGETS