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Parity violation in proton-proton scattering at 221 MeV
A R Berdoz1, J Birchall, J B Bland
1Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
Physical Review Letters
|January 22, 2002
Summary
Researchers measured the parity-violating longitudinal analyzing power in proton-proton scattering. This provides crucial data for understanding the weak force in nuclear interactions.
Area of Science:
- Nuclear Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- Parity violation in the nuclear force is a subtle but important phenomenon.
- Understanding the weak interaction's role in nucleon-nucleon forces is a key challenge.
- Previous measurements of parity violation in proton-proton scattering have provided limited constraints.
Purpose of the Study:
- To precisely measure the parity-violating longitudinal analyzing power, A(z), in proton-proton elastic scattering at 221 MeV.
- To isolate and constrain specific weak meson-nucleon coupling constants, particularly h(pp)(rho).
- To advance the determination of weak meson-nucleon coupling constants by combining new data with existing measurements.
Main Methods:
- Utilizing a polarized proton beam (pvector) incident on a proton target.
- Measuring the longitudinal analyzing power A(z) in elastic proton-proton scattering at a specific energy (221 MeV).
- Analyzing the scattering data to extract the parity-violating amplitude and subsequently the coupling constants.
Main Results:
- The parity-violating longitudinal analyzing power A(z) was measured to be [0.84 ± 0.29(stat) ± 0.17(syst)] x 10^-7.
- This measurement uniquely selects the (3P2 - 1D2) parity-violating transition amplitude.
- The result directly constrains the weak meson-nucleon coupling constant h(pp)(rho).
Conclusions:
- The experiment successfully measured a key parity-violating observable in proton-proton scattering.
- The data provides a direct constraint on the weak meson-nucleon coupling constant h(pp)(rho).
- Combined with prior data, this work enables the first simultaneous determination of h(pp)(rho) and h(pp)(omega).
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