No description available.

Thesis (Ph. D. in Physics)--University of California, Berkeley, Sept. 1955. / Includes bibliographical references (p. 71-73). 68

No description available.

Graduation date: 1997

Thesis supervisor: Onel Yasar. Includes bibliographic references (p. 73-74).

A first coincident measurement of the pion induced pion production reaction cross-section on a complex nucleus (A > 2) has been successfully performed. In particular, the reaction ¹⁶O(π⁺,π⁺,π⁻) was measured at 280 MeV incident pion energy. The only previous published measures of this reaction on nuclei consisted of a dated measurement done on emulsion nuclei [BBD*69] and did not provide very stringent limits to the nuclear cross section. Single arm experiments have previously been done elsewhere on the proton [BJK*80] and the deuteron [PGM*84]. The reaction was measured at TRIUMF using the QQD magnetic spectrometer in coincidence with the CARUZ [RGR88], a total absorption scintillator range telescope. The measured four-fold differential cross sections were extrapolated to the unmeasured portions of the phase-space to extract the total reaction cross-section at 280 MeV, which was found to be σtot = 2.250 ± .350m6. The (π,2π) cross-section is thus observed to provide approximately 40% of the inclusive double charge exchange cross section [Woo84] at this energy. The model of [OV86] is found to explain many of the features of the data, including σtot. The present data do not preclude effects due to pion condensate precursor phenomena as proposed by [CE83] but they do not support the existence of a strong effect. The data are also compared to kinematical Monte Carlo simulations of some possible reaction mechanisms and it is found that the presence of an intermediate ∆ can aid the explanation of the low energy features of the π⁺ energy spectrum. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The reaction p+p → p+p+π⁰ has been studied from threshold up to 500 MeV, by detecting the decay 7-rays of the π⁰ in coincidence in two large NaI crystals (TINA and MIN A). It was possible to measure the energy spectra, the differential cross sections and the asymmetry of the π⁰. The total cross sections and the angular distribution parameter b (defined by [Formula Omitted] determined in this measurement are consistent with previous measurements, but are of a much higher precision. The value obtained for b is very small indicating that most of the π⁰ mesons are isotropically distributed in the centre of mass. Assuming the energy spectra predicted by Gell-Mann, we have deduced the intensities of the Ss, Ps and Pp transitions by a global fit to all the energy spectra and the resulting cross sections. For Ss we obtained [Formula Omitted] which is smaller and more accurate than the previous measurements. A model independent [Formula Omitted] would have an uncertainty of about 6 µb. We have compared our results with those of the reaction n+p → N + N + π± and found them to be fairly similar. Any difference would demand inelasticities in the 1=0 channels, but the total cross sections indicate that σ₀₁ is small. The centre of mass pion energy spectra for pp → ppπ⁰ and np → nnπ⁺ are also similar. However a large cosΦ term is observed in the π± differential cross sections from the np reaction which is an indication of a significant value for σ₀₁. The analysing powers are fairly large and negative. This is the first measurement of this observable, although evidence from the reaction ¹³C(p, π⁻) had suggested that the asymmetry in the free pn → ppπ⁻ reaction might be positive. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

Thesis (Ph. D.)--Ohio University, August, 2004. / Includes bibliographical references (p. 113-117).

Thesis (Ph.D.)--University of California, Berkeley, 1962. / "UC-34 Physics" -t.p. "TID-4500 (17th Ed.)" -t.p. Includes bibliographical references (p. 81-83).