New physics in the angular distribution of $B_c^{-}\to J/\psi (\to {\mu }^{+}{\mu }^{-}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ decay

Abstract

In $B_c^{-}\to J/\psi (\to {\mu }^{+}{\mu }^{-}){\tau }^{-}{\bar{\nu }}_{\tau }$ decay, the three-momentum ${\mathbf{p}}_{{\tau }^{-}}$ cannot be determined accurately due to the decay products of ${\tau }^{-}$ inevitably include an undetected ${\nu }_{\tau }$. As a consequence, the angular distribution of this decay cannot be measured. In this work, we construct a {\it measurable} angular distribution by considering the subsequent decay ${\tau }^{-}\to {\pi }^{-}{\nu }_{\tau }$. The full cascade decay is $B_c^{-}\to J/\psi (\to {\mu }^{+}{\mu }^{-}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$, in which the three-momenta ${\mathbf{p}}_{{\mu }^{+}}$, ${\mathbf{p}}_{{\mu }^{-}}$, and ${\mathbf{p}}_{{\pi }^{-}}$ can be measured. The five-fold differential angular distribution containing all Lorentz structures of the new physics (NP) effective operators can be written in terms of twelve angular observables ${\mathcal{I}}_i(q^2,E_{\pi })$. Integrating over the energy of pion $E_{\pi }$, we construct twelve normalized angular observables ${\hat{\mathcal{I}}}_i(q^2)$ and two lepton-flavor-universality ratios $R(P_{L,T}^{J/\psi })(q^2)$. Based on the $B_c\to J/\psi$ form factors calculated by the latest lattice QCD and sum rule, we predict the $q^2$ distribution of all ${\hat{\mathcal{I}}}_i$ and $R(P_{L,T}^{J/\psi })$ both within the Standard Model and in eight NP benchmark points. We find that the benchmark BP2 (corresponding to the hypothesis of tensor operator) has the greatest effect on all ${\hat{\mathcal{I}}}_i$ and $R(P_{L,T}^{J/\psi })$, except ${\hat{\mathcal{I}}}_5$. The ratios $R(P_{L,T}^{J/\psi })$ are more sensitive to the NP with pseudo-scalar operators than the ${\hat{\mathcal{I}}}_i$. Finally, we discuss the symmetries in the angular observables and present a model-independent method to determine the existence of tensor operators.

29 pages, 3 figures, matches to the version published in JHEP

References in corpus (34)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• Combined Measurement of the Higgs Boson Mass in $pp$ Collisions at $\sqrt{s}=7$ and 8 TeV with the ATLAS and CMS Experiments
• The lifetime of the $B_c^{-}$ meson and the anomalies in $B\to D^{(\ast )}\tau \nu$
• New physics in the weak interaction of $\bar{B}\to D^{(\ast )}\tau \bar{\nu }$
• Exclusive semileptonic and nonleptonic decays of the Bc meson
• 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
• Study of exclusive semileptonic and nonleptonic decays of $B_c^{-}$ in a nonrelativistic quark model
• New Physics effect on $B_c\to J/\psi \tau \bar{\nu }$ in relation to the $R_{D^{(\ast )}}$ anomaly
• The semileptonic decay Lambda_b -> Lambda_c + tau(-) + antinu_tau in the covariant confined quark model
• Charged-Higgs effects in a new B -> D tau nu differential decay distribution
• New physics reach of the decay mode $\bar{B}\to {\bar{K}}^{\ast 0}{\ell }^{+}{\ell }^{-}$
• ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ Decay in the Standard Model and with New Physics
• New Physics in the Visible Final States of $B\to D^{(\ast )}\tau \nu$
• Consequences of R-Parity violating interactions for anomalies in $\bar{B}\to D^{(\ast )}\tau \bar{\nu }$ and $b\to s{\mu }^{+}{\mu }^{-}$
• 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
• $R(J/\psi )$ and $B_c^{-}\to J/\psi {\ell }^{-}{\bar{\nu }}_{\ell }$ Lepton Flavor Universality Violating Observables from Lattice QCD
• Semitauonic $b$-hadron decays: A lepton flavor universality laboratory
• Estimation of Semileptonic Decays of $B_c$ Meson to S-wave Charmonia with NRQCD
• On lepton flavour universality in semileptonic $B_c\to {\eta }_c,J/\psi$ decays
• The role of right-handed neutrinos in $b\to c\tau \bar{\nu }$ anomalies
• $B_c\to J/\psi$ Form Factors for the full $q^2$ range from Lattice QCD
• ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ decay in scalar and vector leptoquark scenarios
• Investigation of Effects of New Physics in ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ Decay
• Probing new physics in semileptonic ${\Lambda }_b$ decays
• Lepton flavor universality violation in semileptonic tree level weak transitions
• CP violation in $B\to D\tau {\nu }_{\tau }$ using multi-pion tau decays
• A Measurable Angular Distribution for $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ Decays
• The measurable angular distribution of ${\Lambda }_b^0\to {\Lambda }_c^{+}(\to {\Lambda }^0{\pi }^{+}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ decay
• A Complete Framework for Tau Polarimetry in $B\to D^{(\ast )}\tau \nu$ Decays
• Signatures of complex new physics in $b\to c\tau \bar{\nu }$ transitions
• Probing new physics in semileptonic ${\Sigma }_b$ and ${\Omega }_b$ decays
• ${\bar{B}}_c\to {\eta }_c$, ${\bar{B}}_c\to J/\psi$ and $\bar{B}\to D^{(\ast )}$ semileptonic decays including new physics
• TeV-scale vector leptoquark from Pati-Salam unification with vectorlike families

Cited by in corpus (2)

• Time-reversal asymmetries in ${\Lambda }_b$ semileptonic decays
• Novel Model-Independent Approach to Explore New Physics in Five-body Semileptonic Decays