Scattering of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>by<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>and of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>by Tritium

The differential elastic scattering cross section has been measured for the scattering of ${\mathrm{He}}^{3}$ from ${\mathrm{He}}^{4}$ and the scattering of ${\mathrm{He}}^{4}$ from tritium for bombarding energies of 5 to 18 and 4 to 18 MeV, respectively. Data were also obtained for the reactions ${\mathrm{He}}^{4}({\mathrm{He}}^{3},p){\mathrm{Li}}^{6}$, ${\mathrm{He}}^{4}({\mathrm{He}}^{3},{p}^{\ensuremath{'}}){\mathrm{Li}}^{6*}$, ${\mathrm{H}}^{3}(\ensuremath{\alpha},n){\mathrm{Li}}^{6}$, and ${\mathrm{H}}^{3}(\ensuremath{\alpha},{n}^{\ensuremath{'}}){\mathrm{Li}}^{6*}$. Levels are seen at 4.65, 6.64, 7.47, and 9.7 MeV in ${\mathrm{Li}}^{7}$, and at 4.57, 6.73, 7.21, and 9.3 MeV in ${\mathrm{Be}}^{7}$. A phase-shift analysis suggests assignments of ${\frac{7}{2}}^{\ensuremath{-}}$ and ${\frac{5}{2}}^{\ensuremath{-}}$ for the two lower levels in ${\mathrm{Li}}^{7}$, confirms the ${\frac{5}{2}}^{\ensuremath{-}}$ assignment of the 7.47 level, and suggests a ${\frac{7}{2}}^{\ensuremath{-}}$ assignment for the new level at 9.7 MeV. Similarly in ${\mathrm{Be}}^{7}$, the assignments of ${\frac{7}{2}}^{\ensuremath{-}}$ and ${\frac{5}{2}}^{\ensuremath{-}}$ for the lower two levels are confirmed, and an assignment of ${\frac{7}{2}}^{\ensuremath{-}}$ is suggested for the new level at 9.3 MeV. The reduced widths for $\ensuremath{\alpha}$ and nucleon emission were determined by fitting the phase shifts near each level with a single- and/or double-level formula from the $R$-matrix formalism of Lane and Thomas. The results of the analysis are discussed and compared with predictions of recent nuclear-model calculations.

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