Research of the scattering process of quasi-particle of superfluid 3He using the fourth sound and the torsional oscillator technique

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Helium 3 is Fermion, so that the mean free path of the quasi particle of helium 3 is proportional to T^<-2> in a degenerate region. At ultra-low temperature it becomes very long and the local field theory cannot be acceptable. In this research, we studied the scattering of the quasi particle of superfluid helium 3 in a situation mentioned above.In this year torsional oscillator experiment has been carried out. Tosee the influence of the boundary condition to the scattering of the quasi particle of helium 3, we used the thin layr of helium 4 on a sample cell wall. As mentioned above, the mean free path of the helium 3 quasi particle becomes very long at the ultra-low temperature, then the result of the experiments should be compared with the theoretical calculation by the slip correction. The measurements were done changing the pressure and the temperature of the sample. The results were compared with that of the experiment without helium 4 layr (pure helium 3 experiment). Our conclusion are,1. The temperature dependence and the amplitude of the viscosity of the liquid helium 3 are not influenced by the helium 4 thin layr. This shows that our measurement method is good.2. We could not detect the effect of the fluctuation just above the superfluid transition temperature.3. The slip length of the normal phase of liquid helium 3 was affected by helium 4 thin layr, especially in 5bar experiment. Its amplitude becomes about twice of the pure helium 3 experiment, however, in 21bar experiment it was not affected. This result is consistent to the fourth sound result of helium 4 thin layr, that the effect of helium 4 thin layr disappears at high pressure.4. The slip length of the superfluid phase of 21 bar experiment does not show the effect by the helium 4 layr. On the other hand, 5bar experiment gives the result that it becomes as twice as pure helium 3 case. This shows that the Andreev reflection occurs even on helium 4 thin layr.