The role of right-handed neutrinos in $b \to c \tau \bar{\nu}$ anomalies

Understand

Motivated by the persistent anomalies reported in the $b\to c\tau\bar{\nu}$ data, we perform a general model-independent analysis of these transitions, in the presence of light right-handed neutrinos.

• We adopt an effective field theory approach and write a low-energy effective Hamiltonian, including all possible dimension-six operators.
• The corresponding Wilson coefficients are determined through a numerical fit to all available experimental data.
• In order to work with a manageable set of free parameters, we define eleven well-motivated scenarios, characterized by the different types of new physics that could mediate these transitions, and analyse which options seem to be preferred by the current measurements.