| Budget Amount *help |
¥14,690,000 (Direct Cost: ¥11,300,000、Indirect Cost: ¥3,390,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2016: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2015: ¥9,100,000 (Direct Cost: ¥7,000,000、Indirect Cost: ¥2,100,000)
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| Outline of Final Research Achievements |
We have studied atomic scatterings of positronium (Ps) in the ultra-low-energy region less than 100 meV by using Ps spin-conversion reaction which is forbidden in the s-wave scatterings (L=0). We have analyzed the data of the Ps annihilation rates and the momentum transfer cross-section in gaseous xenon obtained by our new positron annihilation spectrometer by means of a partial-wave expansion method. We have determined the Ps-Xe scattering length to be 2.06 a.u., which indicates that the Xe potential push out the Ps wave and delays the phase while the long-range interaction is van der Waals force. This results are qualitatively consistent with some theoretical predictions; however, some quantitative discrepancies are remained to be studied in the future works.
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