| 日時: |
2001-06-08 16:00 - |
| 場所: |
Room 345 in the 4th Building |
| 会議名: |
Improved Extraction of V_ub from the Inclusive Semileptonic b --> uDeca Rate\ |
| 講演者: |
Dr. Victor Elias (Department of Applied Mathematics, University of Western Ontario) |
| 講演言語: |
英語 |
| アブストラクト: |
Asymptotic Pade approximant methods are employed to estimate the hree-loop order coefficients within the MS-bar expression for the semileptonic weak decay of a b-quark into a u-quark. All coefficients of
(nonzero) powers of renormalization-scale logarithms are also obtained via
application of the appropriate renormalization group (RG) equation for this
process. The relative errors of asymptotic Pade approximant estimates of such
coefficients is found to be within 5.1% of their true RG values. A similar
asymptotic Pade approximant estimate is presented of the constant
(logarithm-independent) contribution to the three-loop order expression, a
term that is not accessible via RG methods alone. The incorporation of this
estimate is seen to reduce the renormalization scale dependence of the total
rate, leading to a substantial reduction in the theoretical uncertainty associated
with the extraction of V_ub. |
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