2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/192596An exact expression for the master integral I_2 arising in three-loop on-shell HQET propagator diagrams with mass is derived and its analytical expansion in the dimensional regularization parameter epsilon is given.6 pages, 1 figure; v3: completely re-written, 2 new authors, many new results, additional referencesHigh Energy Physics - Phenomenologytext