Measurement of spin parameters in inclusive. Lambda. and K sub S production using a polarized proton beam

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5065993

Tonse, S R

A polarized proton beam incident on a Beryllium target was used for inclusive {Lambda}(1116 meV) production at beam momenta of 13.3 GeV and 18.5 GeV. The beam polarization was transverse to the beam direction with magnitude 0.63(0.40) at 13.3(18.5) GeV. The trigger condition favored forward produced {Lambda}'s with moderately high p{sub T}(p{sub T} {approximately} 1GeV). The {Lambda} polarization was measured and found to be in agreement with results from earlier experiments which used unpolarized proton beams. Analyzing power (A) and depolarization (D{sub NN}) of the {Lambda}'s were both measured and compared with a hyperon polarization model in which the polarization arises from a Thomas precession effect. There is good agreement with its predictions: A = 0 and D{sub NN} = 0. In particular, our measurement of D{sub NN} = {minus}0.009 {plus minus} 0.015 supports the idea that the valence quarks carry all of the hadron spin, since this assumption is implicit in the model's use of SU(6) wave functions to form final state hadrons from beam fragments and sea quarks. The analyzing power of K{sub s} was also measured at 13.3(18.5)GeV and found to be {minus}0.094 {plus minus} 0.012 ({minus}0.076 {plus minus} 0.015). We use the same model to predict A of K{sub s}, taking into account K{sub s} production from various sources (K{degree}, K{degree} and K*) and find good agreement with the data. Finally a small sample of {Lambda} was isolated form the 18.5 GeV sample and was found to have A = 0.03 {plus minus} 0.1, consistent with the model's prediction of zero.

• Research Organization: Rice Univ., Houston, TX (USA)
• OSTI ID: 5065993
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101* -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
645100 -- High Energy Physics-- Particle Interactions & Properties-Experimental
651000 -- Nuclear Physics
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH METALS
BEAMS
BERYLLIUM
DATA
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
EXPERIMENTAL DATA
GEV RANGE
GEV RANGE 10-100
HADRONS
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUCLEON BEAMS
NUMERICAL DATA
PARTICLE BEAMS
PRODUCTION
PROTON BEAMS