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.

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