Related papers: Towards two- and three-loop QCD corrections to the…

We report on the calculation of next-to-next-to-leading order (NNLO) QCD corrections to the width difference $\Delta \Gamma_s$ in the neutral $B$-meson mixing process $B^0_s - \bar{B}^0_s$. These contributions represent an important step in…

The width difference $\Delta \Gamma$ among the two mass eigenstates of the $B_s$-$\bar B_s$ system is measured with a precision of 7%. The theory prediction has a larger uncertainty which mainly stems from unknown perturbative higher-order…

This report summarises recent advances made in the calculation of the NNLO QCD corrections to the width difference $\Delta\Gamma_s$ in the $B_s-\overline{B}_s$ system. The inclusion of the effects due to current-current operators leads to…

We extend the theoretical prediction for the width difference $\Delta \Gamma_q$ in the mixing of neutral $B$ mesons in the Standard Model to next-to-next-to-leading order in $\alpha_s$. To this aim we calculate three-loop diagrams with two…

This report summarises important technical challenges and their solutions in the calculation of the next-to-next-to-leading order QCD corrections to the width difference $\Delta\Gamma_s$ in the $B_s-\overline{B}_s$ system. We focus on the…

We consider two-loop QCD corrections to the element $\Gamma_{12}^q$ of the decay matrix in $B_q-\bar{B}_q$ mixing, $q=d,s$, in the leading power of the Heavy Quark Expansion. The calculated contributions involve one current-current and one…

We use the heavy quark expansion to investigate the width difference $\Delta\Gamma_{B_s}$ between the $B_s$ mass eigenstates. The corrections of ${\cal O}(\Lambda_{QCD}/m_b)$ and ${\cal O}(m_s/m_b)$ to the leading order expression in the…

We calculate a class of three-loop Feynman diagrams which contribute to the next-to-next-to-leading logarithmic approximation for the width difference $\Delta\Gamma_{s}$ in the $B_s-\bar{B}_s$ system. The considered diagrams contain a…

We present lattice QCD results for the matrix elements of $R_2$ and other dimension-7, $\Delta B = 2$ operators relevant for calculations of $\Delta \Gamma_s$, the $B_s-\bar{B}_s$ width difference. We have computed correlation functions…

In this contribution the QCD next-to-next-to-leading order (NNLO) matching coefficients to the branching ratio $B_s \to \mu^+ \mu^-$ in the Standard Model (SM) and to $\bar{B}\to X_s \gamma$ in the Two Higgs Doublet Model (2HDM) are…

We compute perturbative matching coefficients to the Heavy Quark Effective Theory representation for the QCD effective local $\Delta B=2$ Hamiltonian that determines the mass difference in $B^0-\bar{B}^0$ system of states. We report on the…

We compute perturbative corrections to matching coefficients of QCD to HQET for the matrix element of the $\Delta B=2$ operator that determines the mass difference in $B^0-\bar{B}^0$ system of states. This involves the technical point of…

Next-to-leading order QCD corrections to the width difference Delta Gamma in the B_s-meson system are presented. I further discuss how Delta Gamma can be used to detect new physics.

The decay $B \to X_s \gamma$ is studied at the Next to Leading Order in QCD in a class of models containing at least two Higgs doublets and with only one charged Higgs boson non-decoupled at low-energy. The two-loop matching condition is…

In this talk I report on the results of a recent calculation of the \alpha_s corrections to a three-point correlation function at the three-loop level in QCD perturbation theory, which allows one to extract the matrix element of B^0 -\bar…

We discuss the calculation of the width difference $\Delta\Gamma_{B_s}$ between the $B_s$ mass eigenstates to next-to-leading order in the heavy quark expansion. $1/m_b$-corrections are estimated to reduce the leading order result by…

We study predictions from perturbative Quantum Chromodynamics (QCD) for the process pp -> H -> gamma gamma + X. In particular, we compare fully differential calculations at next-to-leading (NLO) and next-to-next-to-leading order (NNLO) in…

We calculate the three-loop master integrals of Ref. [1] [arXiv:1709.02160] in analytic form. This allows us to present the fermionic contributions to the $\Delta B=2$ Wilson coefficients of the $B$-$\bar B$ decay matrix in…

We present the results of the calculation of QCD corrections to the matching conditions for the Wilson coefficients of operators mediating the transition b->s l^+l^- in the context of the MSSM. Within a scenario with decoupled heavy gluino…

We compute the QCD corrections to the decay rate difference in the $B_s-\bar B_s$ system, $\Delta\Gamma_{B_s}$, in the next-to-leading logarithmic approximation using the heavy quark expansion approach. Going beyond leading order in QCD is…