New Physics in inclusive $\bar{B}\to X_c\ell \bar{\nu }$ decays

Abstract

We present the first global phenomenological fit of inclusive $\bar{B}\to X_c\ell \bar{\nu }$ observables to all available experimental data allowing for generic dimension-six New Physics interactions in the Weak Effective Theory. The fit includes both New Physics Wilson coefficients and non-perturbative QCD parameters. New Physics contributions are calculated including power corrections up to $\mathcal{O}({\Lambda }_{\mathrm{QCD}}^3/m_b^3)$ and perturbative QCD corrections up to $\mathcal{O}({\alpha }_s)$. We find no significant preference for New Physics and obtain bounds on the size of the relevant Wilson Coefficients competitive with those coming from exclusive modes.

Contribution to the 2026 Electroweak session of the 60th Rencontres de Moriond