Exploring the $\tau$ polarization in $B\to X\tau \bar{\nu }$ along different axes

Abstract

The $\tau$ polarization in semileptonic $B$ decays provides probes of new physics complementary to decay rate distributions of the three-body final state. Prior calculations for inclusive decays used a definition for the polarization axis that is different from the choice used in calculations (and the only measurement) for exclusive channels. To compare inclusive and exclusive predictions, we calculate the $\tau$ polarization in inclusive $B\to X\tau \bar{\nu }$ using the same choice as in the exclusive decays, and construct a sum rule relating the inclusive $\tau$ polarization to a weighted sum of exclusive decay polarizations. We use this relation, experimental data, and theoretical predictions for the decays to the lightest charm or up-type hadrons to make predictions for excited channels.

arXiv comment6 pages, 2 figures

References in corpus (30)

• FLAG Review 2021
• QCD Predictions for Lepton Spectra in Inclusive Heavy Flavour Decays
• Inclusive Semileptonic B and Polarized Lambda_b Decays from QCD
• Reparameterisation Invariance Constraints on Heavy Particle Effective Field Theories
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Differential Distributions in Semileptonic Decays of the Heavy Flavors in QCD
• New physics in the weak interaction of $\bar{B}\to D^{(\ast )}\tau \bar{\nu }$
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ with one-prong hadronic $\tau$ decays at Belle
• B decays in the upsilon expansion
• $|V_{ub}|$ from $B\to \pi \ell \nu$ decays and (2+1)-flavor lattice QCD
• Diagnosing New Physics in $b\to c\tau {\nu }_{\tau }$ decays in the light of the recent BaBar result
• Charged Higgs Effects on Exclusive Semi-tauonic $\bbox{B}$ Decays
• Heavy Quark Expansion for the Inclusive Decay $\bar{B}\to \tau \bar{\nu }X$
• Tau longitudinal polarization in B -> D tau nu and its role in the search for charged Higgs boson
• Probing new physics in ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ using the longitudinal, transverse, and normal polarization components of the tau lepton
• The Inclusive $\bar{B}\to \tau \bar{\nu }X$ Decay in Two Higgs Doublet Models
• Semileptonic $B_{(s)}$ decays to excited charmed mesons with $e,\mu ,\tau$ and searching for new physics with $R(D^{\ast \ast })$
• A Model Independent Determination of |V_{ub}|
• Model independent analysis of semileptonic $B$ decays to $D^{\ast \ast }$ for arbitrary new physics
• Precise predictions for B -> Xc tau nu decay distributions
• Transverse Tau Polarization in Decays of the Top and Bottom Quarks in the Weinberg Model of CP Non-conservation
• Constrained second-order power corrections in HQET: $R(D^{(\ast )})$, $|V_{cb}|$, and new physics
• On the Inclusive Determination of V_{ub} from the Lepton Invariant Mass Spectrum
• The B -> pi tau nu decay in the context of the 2HDM type II
• $B\to \rho l\bar{\nu }$ and $\omega l\bar{\nu }$ in and beyond the Standard Model: Improved predictions and $|V_{ub}|$
• Tau lepton distributions in semileptonic B decays
• The role of right-handed neutrinos in $b\to c\tau (\pi {\nu }_{\tau },\rho {\nu }_{\tau },\mu {\bar{\nu }}_{\mu }{\nu }_{\tau }){\bar{\nu }}_{\tau }$ from visible final-state kinematics
• Transverse tau polarization in inclusive $\bar{B}\to \tau \bar{\nu }X$ decays
• New physics and the tau polarization vector in $b\to c\tau {\bar{\nu }}_{\tau }$ decays
• Polarization of tau leptons in semileptonic B decays

Cited by in corpus (1)

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