STUDY OF $pi$$sup -$ + p $Yields$ $pi$$sup -$ + $pi$$sup +$ + n AT 1.25 AND 1.75 Bev/c FOR LOW-NUCLEON-MOMENTUM-TRANSFER COLLISIONS: EVIDENCE FOR PION-PION INTERACTIONS (thesis)

Technical Report · Wed Feb 27 04:00:00 EST 1963

OSTI ID:4719036

Johnson, W B

The interaction pi /sup -/-p carbon materia pi /sup -/- pi /sup +/-n at incident pion momenta of 1.25 and 1.75 Bev/c was studied. Two arrays of plastic scintillation counters were used to detect the final-state particles; the first array---15 cm thick, and 160 cm from the liquid-hydrogen target where the interaction occurred ---detected both pions and neutrons in the forward pi steradians; a second array of thin scintillators, placed near the hydrogen target, was used to detect pions in the remaining angular region. The energy of the neutron was determined by measuring its flight time from the liquid hydrogen target to the first array. Only neutrons from 5 to 65 Mev were detected, thus limiting the study to those collisions in which the four-momentum transfer squared from the proton to the neutron was less than 6.5 mu /sup 2/ (where mu is the mass of the pion). Study of the data as a function of the mass'' of the two-pion final-state system corroborates the presence of a pion-pion resonance at a mass value of 750 Mev. The width of the resonance is somewhat greater than that found in experiments dealing with other charge states. An attempt was made to extract pion-pion total cross sections from the data by the Chew-Low extrapolation method. The results obtained are physically untenable and indicate failure of the extrapolation method when applied to these data. Considerable evidence is found for final-state interaction between the neutron and one of the pions. The data are subjected to the Treiman-Yang test to discover any deviations from the one-pion-exchange model; considerable deviation is found for large momentum-transfer collisions. It is felt that the large resonance width and the failure of the Chew-Low extrapolation method are results of final-state interactions not accounted for in the one-pion-exchange model. 33 references. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• NSA Number: NSA-17-024277
• OSTI ID: 4719036
• Report Number(s): UCRL-10703
• Country of Publication: United States
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
BIBLIOGRAPHY
COLLISIONS
CROSS SECTIONS
ELECTRIC CHARGES
ELEMENTARY PARTICLES
ENERGY
ENERGY LEVELS
ENERGY RANGE
HYDROGEN
INTERACTIONS
LIFETIME
LIQUIDS
MASS
MEASURED VALUES
MOMENTUM
NEUTRONS
NUMERICALS
OPE MODEL
PARTICLE MODELS
PHOSPHORS
PHYSICS
PIONS
PROTONS
RESONANCE
SCINTILLATION COUNTERS
TARGETS
VELOCITY