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 $|V_{cb}|$.

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

References in corpus (4)

• New physics in the weak interaction of $\bar{B}\to D^{(\ast )}\tau \bar{\nu }$
• Precision determination of the CKM element Vcb
• Can the differences in the determinations of $V_{ub}$ and $V_{cb}$ be explained by New Physics?
• Limits on New Physics from exclusive $B\to D^{(\ast )}\ell \bar{\nu }$ Decays

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• Loopy Determinations of $V_{ub}$ and $V_{cb}$
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• New physics contributions to moments of inclusive $b\to c$ semileptonic decays
• Probing New Physics in light of recent developments in $b\to c\ell \nu$ transitions
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• Angular analysis of $\bar{B}\to D_2^{\ast }(\to D\pi )\ell \bar{\nu }$ decay and new physics
• Nonleptonic $B_c$ decay rates from model independent relations
• $\frac{|V_{ub}|}{|V_{cb}|}$ and Quest for New Physics
• Chirality structure of vector like new physics operators in charged current transitions
• Impact of Lattice QCD on CKM Phenomenology
• Probing New Physics with heavy hadron decays