Seminarium "Teoria cząstek elementarnych i kosmologia"

The inclusive radiative decay of the B meson is known to provide strong constraints on new particles and their interactions. In 2015, some of the important NNLO QCD corrections were determined using interpolation in the charm quark mass. An uncertainty due to such an interpolation in the predicted branching ratio was estimated at the ⁺_-3% level, which should be compared to around ⁺_-5% uncertainty in the experimental world average. In my talk, I will present yet unpublished preliminary results for the considered correction at the physical charm quark mass, which removes the need for interpolation and the associated uncertainty. I will discuss basic steps of the calculation that required evaluation of four-loop propagator diagrams with unitarity cuts in the presence of two mass scales. Next, I will discuss the phenomenological impact of the considered correction on the predicted branching ratio in the SM, as well as the resulting bounds on the charged Higgs boson mass in the Two-Higgs-Doublet Model II.