# Heavy-quark form factors in the large $\beta _0$ limit

The European Physical Journal C, Jul 2017

Heavy-quark form factors are calculated at $\beta _0 \alpha _s \sim 1$ to all orders in $\alpha _s$ at the first order in $1/\beta _0$. Using the inversion relation generalized to vertex functions, we reduce the massive on-shell Feynman integral to the HQET one. This HQET vertex integral can be expressed via a ${}_2F_1$ function; the nth term of its $\varepsilon$ expansion is explicitly known. We confirm existing results for $n_l^{L-1} \alpha _s^L$ terms in the form factors (up to $L=3$), and we present results for higher L.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-017-5021-4.pdf

Andrey G. Grozin. Heavy-quark form factors in the large $\beta _0$ limit, The European Physical Journal C, 2017, 453, DOI: 10.1140/epjc/s10052-017-5021-4