Search for structure in the low-energy antiproton-proton annihilation cross section

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6265080

Jastrzembski, E A

We have measured relative cross sections for the annihilation of antiproton and proton into one or more charged particles. Our investigation was a search for narrow structure in the invariant mass range 1920 to 1960 MeV. The study was motivated by a notable disagreement among past experimental results. While several experiments have reported a narrow structure, labelled the S(1935), anti pp total, elastic, and annihilation cross sections, others failed to confirm this structure. Among those who reported its existence, a lack of agreement on such fundamental parameters as mass, width, and rate of production was apparent. In our study we have used a new long target method particularly suited to search for narrow structure. The use of an incident beam momentum of about 600 MeV/c and one meter long target of liquid hydrogen allows the simultaneous detection of annihilations from antiprotons with momentum in the range 600 to 400 MeV/c. Multiwire proportional chambers detect the charged annihilation products to fix the interaction point, and hence, by the use of the range-energy relation, the momentum at interaction. This removes several problems common to other electronic experiments such as the difficulty of obtaining adequate invariant mass resolution and the difficulty of normalizing data taken at many beam momenta. No narrow enhancements have been observed in our data. We set a 90% confidence level upper limit on a simple Breit-Wigner enhancement in the S region (1930 to 1942 MeV) of width 4 MeV or narrower at 14 mb-MeV.

• Research Organization: Temple Univ., Philadelphia, PA (USA)
• OSTI ID: 6265080
• Country of Publication: United States
• Language: English

Related Subjects

645101* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Electromagnetic Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
BARYON-BARYON INTERACTIONS
BARYONIUM
BASIC INTERACTIONS
BOSONS
DATA
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY RANGE
EXOTIC RESONANCES
EXPERIMENTAL DATA
HADRON-HADRON INTERACTIONS
HADRONS
INFORMATION
INTERACTIONS
MESON RESONANCES
MESONS
MEV RANGE
MEV RANGE 100-1000
NUCLEON-ANTINUCLEON INTERACTIONS
NUMERICAL DATA
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PROTON-ANTIPROTON INTERACTIONS
RESONANCE PARTICLES
S-1930 RESONANCES