An experimental investigation of the absorption reaction ⁴He(π⁺,ppp) has been undertaken on the M11 beamline at the TRIUMF cyclotron. Positive pions at an average kinetic energy of 165 MeV were directed onto a cylindrical liquid 4He target and the outgoing protons were measured by a combination of two time-of-flight arrays and two plastic scintillator telescopes. A description of the apparatus, experimental technique and calibration is presented.
Results from triple proton coincidences at a single orientation of three of the detectors are discussed. Their angular settings with respect to the pion beam were 40°, 136° and —55°. Comparisons are made with Monte-Carlo simulations of three and four body phase spaces. Identification of a quasi-free three nucleon absorption mode is made for the first time at this energy. An integrated cross-section for this process is determined (σQ₃N = 4.4 ± 0.6mb). The quantitative agreement between these results and those of another recent experiment¹ indicate that a small fraction(≈10%) of the coincidences could be due to a two step absorption mechanism.
¹Backenstoss et al. Phys. Rev. Lett 61:923(1988) / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/27985 |
| Date | January 1988 |
| Creators | McAlister, John |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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