Tension in the inclusive versus exclusive determinations of $|V_{cb}|$: a possible role of new physics

Abstract

We reconsider the possibility that the tension in the $|V_{cb}|$ determinations from inclusive and exclusive $B$ decay modes is due to a new physics effect. We modify the Standard Model effective Hamiltonian for semileptonic $b\to c$ transitions including a tensor operator with a lepton flavour dependent coupling ${\epsilon }_T^{\ell }$, and investigate separately the muon and electron modes. The interference term between SM and NP, proportional to the lepton mass, has different impact in the inclusive and exclusive $B$ modes to muon. Moreover, even when the lepton mass is small as for the electron, the NP effect is different in inclusive and exclusive $B$ channels. For both $\mu$ and $e$ we find a region of ${\epsilon }_T^{\mu ,e}$ where the constraints from $B^{-}\to D^{(\ast )0}{\ell }^{-}{\bar{\nu }}_{\ell }$ and $B\to X_c\ell {\bar{\nu }}_{\ell }$ are satisfied for the same $|V_{cb}|$.

arXiv commentRevTex, 6 pages, 7 figures. One reference added; matches published version

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• Footprints of New Physics in $b\to c\tau \nu$ Transitions
• $R(D^{(\ast )})$ from $W^{\prime }$ and right-handed neutrinos
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• Role of $B_c^{+}\to B_{s,d}^{(\ast )}\bar{\ell }{\nu }_{\ell }$ in the Standard Model and in the search for BSM signals
• New physics in inclusive semileptonic $B$ decays including nonperturbative corrections
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• Relations among $B_c\to J/\psi ,{\eta }_c$ form factors
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• On sum rules for semi-leptonic $b\to c$ and $b\to u$ decays
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• Relations between $b\to c\tau \nu$ Decay Modes in Scalar Models
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• Nonleptonic $B_c$ decay rates from model independent relations
• Impact of Lattice QCD on CKM Phenomenology
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• Probing New Physics with heavy hadron decays