Next-to-next-to-leading QCD corrections to the ${\mathbf{B}}^{+}$-${\mathbf{B}}_{\mathbf{d}}^0$, ${\mathbf{D}}^{+}$-${\mathbf{D}}^0$, and ${\mathbf{D}}_{\mathbf{s}}^{+}$-${\mathbf{D}}^0$ lifetime ratios

Francesco Moretti, Ulrich Nierste, Pascal Reeck +1

The total decay widths of heavy mesons can be systematically calculated in terms of an expansion in the two parameters $1/m_Q$ and ${\alpha }_s(m_Q)$, where $Q=c,b$ denotes the heavy quark…