Matching QCD and heavy-quark effective theory heavy-light currents at two loops and beyond
Oct, 199425 pages
Published in:
- Phys.Rev.D 52 (1995) 4082-4098
e-Print:
- hep-ph/9410240 [hep-ph]
Report number:
- OUT-4102-52
Citations per year
Abstract:
Heavy--light QCD currents are matched with HQET currents at two loops and leading order in . A single formula applies to all current matchings. As a by--product, a master formula for the two--loop anomalous dimension of the QCD current is obtained, yielding a new result for the tensor current. The dependence of matching coefficients on prescriptions is elucidated. Ratios of QCD matrix elements are obtained, independently of the three--loop anomalous dimension of HQET currents. The two--loop coefficient in is with light flavours, and a correction, , that takes account of the non--zero ratio . Fastest apparent convergence would entail at MeV. ``Naive non--abelianization'' of large-- results, via , gives reasonable approximations to exact two--loop results. All--order results for anomalous dimensions and matching coefficients are obtained at large . Consistent cancellation between infrared-- and ultraviolet--renormalon ambiguities is demonstrated.- quark: current
- quark: flavor
- quark: mass
- mass: quark
- expansion: mass
- mass: expansion
- renormalization
- quantum chromodynamics
- HQET model
- correction: higher-order
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