Hadron and lepton tensors in semileptonic decays including new physics

Abstract

We extend our general framework for semileptonic decay, originally introduced in N. Penalva et al. [Phys. Rev. D100, 113007 (2019)], with the addition of new physics (NP) tensor terms. In this way, all the NP effective Hamiltonians that are considered in lepton flavour universality violation (LFUV) studies have now been included. Besides, we now also give general expressions that allow for complex Wilson coefficients. The scheme developed is totally general and it can be applied to any charged current semileptonic decay, involving any quark flavors or initial and final hadron states. We show that all the hadronic input, including NP effects, can be parametrized in terms of 16 Lorentz scalar structure functions. In the second part of this work, we use this formalism to obtain the complete NP effects in the ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ semileptonic decay, where LFUV, if finally confirmed, is also expected to be seen. We stress the relevance of the center of mass (CM) $d^2\Gamma /(d\omega d\cos {\theta }_{\ell })$ and laboratory (LAB) $d^2\Gamma /(d\omega d{E}_{\ell })$ differential decay widths. While models with very different strengths in the NP terms give the same differential $d\Gamma /d\omega$ and total decay widths for this decay, they predict very different numerical results for some of the $\cos {\theta }_{\ell }$ and $E_{\ell }$ coefficient-functions that determine the above two distributions. Thus, the combined analysis of the CM $d^2\Gamma /(d\omega d\cos {\theta }_{\ell })$ and LAB $d^2\Gamma /(d\omega d{E}_{\ell })$ differential decay widths will help clarifying what kind of NP is a better candidate in order to explain LFUV.

arXiv comment24 latex pages, 7 figures, 1 table. A few typos corrected. Accepted for publication in Physical Review D

References in corpus (33)

• Dimension-Six Terms in the Standard Model Lagrangian
• Heavy Quark Symmetry
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Evidence for an excess of B -> D(*) Tau Nu decays
• Measurement of an Excess of B -> D(*) Tau Nu Decays and Implications for Charged Higgs Bosons
• Measurement of the branching ratio of $\bar{B}\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to $\bar{B}\to D^{(\ast )}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with hadronic tagging at Belle
• Measurement of the ratio of branching fractions $\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\tau }^{-}{\overline{\nu }}_{\tau })/\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\mu }^{-}{\overline{\nu }}_{\mu })$
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$
• On the B to D* tau nu Sensitivity to New Physics
• Measurement of the branching ratio of ${\bar{B}}^0\to D^{\ast +}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with a semileptonic tagging method
• Model-independent description of $B\to \pi l\nu$ decays and a determination of $|V_{ub}|$
• Measurement of the ratio of the $B^0\to D^{\ast -}{\tau }^{+}{\nu }_{\tau }$ and $B^0\to D^{\ast -}{\mu }^{+}{\nu }_{\mu }$ branching fractions using three-prong $\tau$-lepton decays
• Revisiting $B\to D\ell \nu$
• Measurement of $\mathcal{R}(D)$ and $\mathcal{R}(D^{\ast })$ with a semileptonic tagging method
• ${\Lambda }_b\to p{\ell }^{-}{\bar{\nu }}_{\ell }$ and ${\Lambda }_b\to {\Lambda }_c{\ell }^{-}{\bar{\nu }}_{\ell }$ form factors from lattice QCD with relativistic heavy quarks
• Review of Lepton Universality tests in B decays
• Extraction of $|V_{cb}|$ from $B\to D^{(\ast )}\ell {\nu }_{\ell }$ and the Standard Model predictions of $R(D^{(\ast )})$
• Global fit to $b\to c\tau \nu$ transitions
• Impact of polarization observables and $B_c\to \tau \nu$ on new physics explanations of the $b\to c\tau \nu$ anomaly
• Phenomenology of ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ using lattice QCD calculations
• Addendum to "Impact of polarization observables and $B_c\to \tau \nu$ on new physics explanations of the $b\to c\tau \nu$ anomaly"
• ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ Decay in the Standard Model and with New Physics
• Precise predictions for ${\Lambda }_b\to {\Lambda }_c$ semileptonic decays
• Measurement of $\mathcal{R}(D)$ and $\mathcal{R}(D^{\ast })$ with a semileptonic tagging method
• New predictions for ${\Lambda }_b\to {\Lambda }_c$ semileptonic decays and tests of heavy quark symmetry
• ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ decay in scalar and vector leptoquark scenarios
• Measurement of the shape of the ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}\overline{\nu }$ differential decay rate
• Semileptonic ${\Lambda }_b\to {\Lambda }_c\ell {\bar{\nu }}_{\ell }$ Transition in Full QCD
• Probing new physics in semileptonic ${\Lambda }_b$ decays
• Angular Analysis of \boldmath ${\Lambda }_b\to {\Lambda }_c(\to \Lambda \pi )\ell \bar{\nu }$
• Further tests of lepton flavour universality from the charged lepton energy distribution in $b\to c$ semileptonic decays: The case of ${\Lambda }_b\to {\Lambda }_c\ell {\bar{\nu }}_{\ell }$
• Probing effects of new physics in ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ decays
• Detailed Study of the Decay Lambda_b --> Lambda_c tau {\bar ν}_τ

Cited by in corpus (13)

• On the single leptoquark solutions to the $B$-physics anomalies
• 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
• 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 and the tau polarization vector in $b\to c\tau {\bar{\nu }}_{\tau }$ decays
• Light-cone Sum Rule Analysis of Semileptonic Decays ${\Lambda }_b^0\to {\Lambda }_c^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$
• ${\bar{B}}_c\to {\eta }_c$, ${\bar{B}}_c\to J/\psi$ and $\bar{B}\to D^{(\ast )}$ semileptonic decays including new physics
• Form-factor-independent test of lepton universality in semileptonic heavy meson and baryon decays
• Time-reversal asymmetries in ${\Lambda }_b$ semileptonic decays
• New physics effects on ${\Lambda }_b\to {\Lambda }_c^{\ast }\tau {\bar{\nu }}_{\tau }$ decays
• Visible energy and angular distributions of the charged particle from the $\tau -$decay in $b\to c\tau (\mu {\bar{\nu }}_{\mu }{\nu }_{\tau },\pi {\nu }_{\tau },\rho {\nu }_{\tau }){\bar{\nu }}_{\tau }$ reactions
• Study of angular observables in exclusive semileptonic $B_c$ decays
• Inclusive quasielastic (anti-)neutrino nucleus scattering within the Standard Model and beyond
• Probing New Physics and CP Violation in ${\nu }_{\tau }n\to {\Lambda }_c{\tau }^{-}({\pi }^{-}{\nu }_{\tau })$ and ${\bar{\nu }}_{\tau }p\to \Lambda {\tau }^{+}({\pi }^{+}{\bar{\nu }}_{\tau })$