Renormalization of HQET at Three Loops

Three-loop propagator diagrams in HQET can be reduced, using integration by parts, to 8 basis integrals: 5 trivial ones, two expressible via 3F2, and one only known up to \epsilon^0. Calculation of the heavy-quark propagator in HQET is considerably simplified by the non-abelian exponentiation theorem.Comment: Talk at the QCD workshop, Martina Franca, 17-20 June, to be published in the Proceedings; LaTeX2e, aipproc document class (included), 7 pages, 7 eps figures (included

Heavy quark form factors in the large β0\beta_0 limit

Heavy quark form factors are calculated at $\beta_0 \alpha_s \sim 1$ to all orders in $\alpha_s$ at the first order in $1/\beta_0$. The $n_f^2 \alpha_s^3$ terms in the recent results [arXiv:1611.07535] for the vector form factors are confirmed, and $n_f^{L-1} \alpha_s^L$ terms for higher $L$ are predicted.Comment: v2: the section on inversion relations extended; v3: 3 refs added, discussion of the hypergeometric function expansion extended; v4: eq. (22) and fig. 5 correcte