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Jul 26 – 30, 2021
Europe/Berlin timezone

NNLO QCD corrections to B-meson mixing

Jul 26, 2021, 2:30 PM


Parallel session talk Flavour Physics and CP Violation T08: Flavour Physics and CP Violation


Vladyslav Shtabovenko (KIT)


The flavor mixing parameter $\Delta \Gamma_{12}^s$ that governs the lifetime differences of neutral $B_s$ mesons suffers from large uncertainties related to the uncalculated perturbative corrections. In this talk I will present new results on the previously unknown NNLO QCD corrections to the $B_s - \bar{B}_s$ mixing process that lead to a reduction of theoretical errors on $\Delta \Gamma_{12}^s$. To this end, we perform a fully analytic evaluation of the current-current correlators at 3 loops, as well as the current-penguin and current-chromomagnetic correlators at 2 loops in the $\Delta B = 1$ effective Hamiltonian. Some interesting aspects of this calculation to be addressed in my talk involve higher-order matching between two effective field theories ($\mathcal{H}_{\textrm{eff}}^{\Delta B = 1}$ and $\mathcal{H}_{\textrm{eff}}^{\Delta B = 2}$), dedicated treatment of evanescent operators in the presence of dimensionally regulated IR divergences, asymptotic expansion of the amplitudes in $m_c/m_b$ up to $\mathcal{O}(m_c^2)$ and the analytic evaluation of the resulting 3-loop on-shell integrals with one mass scale.

Collaboration / Activity -
First author Vladyslav Shtabovenko

Primary author


Marvin Gerlach (KIT) Matthias Steinhauser (KIT) Ulrich Nierste (Karlsruhe Institute of Technology)

Presentation materials