Radiatively corrected lepton energy distributions in top quark decays $t\to b{W}^{+}\to b({\ell }^{+}{\nu }_{\ell })$ and $t\to b{H}^{+}\to b({\tau }^{+}{\nu }_{\tau })$ and single charged prong energy distributions from subsequent ${\tau }^{+}$ decays

Abstract

We calculate the QED and QCD radiative corrections to the charged lepton energy distributions in the dominant semileptonic decays of the top quark $t\to b{W}^{+}\to b({\ell }^{+}{\nu }_{\ell })$ $(\ell =e,\mu ,\tau )$ in the standard model(SM), and for the decay $t\to b{H}^{+}\to b({\tau }^{+}{\nu }_{\tau })$ in an extension of the SM having a charged Higgs boson $H^{\pm }$ with $m_{H^{\pm }}<m_t-m_b$. The QCD corrections are calculated in the leading and next-to-leading logarithmic approximations, but the QED corrections are considered in the leading logarithmic approximation only. These corrections are numerically important for precisely testing the universality of the charged current weak interactions in $t$-quark decays. As the ${\tau }^{+}$ leptons arising from the decays $W^{+}\to {\tau }^{+}{\nu }_{\tau }$ and $H^{+}\to {\tau }^{+}{\nu }_{\tau }$ are predominantly left- and right-polarised, respectively, influencing the energy distributions of the decay products in the subsequent decays of the ${\tau }^{+}$, we work out the effect of the radiative corrections on such distributions in the dominant (one-charged prong) decay channels ${\tau }^{+}\to {\pi }^{+}{\bar{\nu }}_{\tau },{\rho }^{+}{\bar{\nu }}_{\tau },a_1^{+}{\bar{\nu }}_{\tau }$ and ${\ell }^{+}{\nu }_{\ell }{\bar{\nu }}_{\tau }$. The inclusive ${\pi }^{+}$ energy spectra in the decay chains $t\to b(W^{+},H^{+})\to b({\tau }^{+}{\nu }_{\tau })\to b({\pi }^{+}{\bar{\nu }}_{\tau }{\nu }_{\tau }+X)$ are calculated, which can help in searching for the induced $H^{\pm }$ effects at the Tevatron and the LHC.

39 pages, 18 figures

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Cited by in corpus (10)

• $\mathcal{O}({\alpha }_s)$ corrections to the B-hadron energy distribution of the top decay in the Minimal Supersymmetric Standard Model considering GM-VFN scheme
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• Improved sensitivity to charged Higgs searches in Top quark decays $t\to b{H}^{+}\to b({\tau }^{+}{\nu }_{\tau })$ at the LHC using $\tau$ polarisation and multivariate tecnniques
• Decays of polarized top quarks to lepton, neutrino and jets at NLO QCD
• Interference effects for the top quark decays $t\to b+W^{+}/H^{+}(\to {\tau }^{+}{\nu }_{\tau })$
• Indirect search for light charged Higgs bosons through the dominant semileptonic decays of top quark $t\to b(\to B/D+X)+H^{+}(\to {\tau }^{+}{\nu }_{\tau })$
• Next-to-leading order corrections to the spin-dependent energy spectrum of hadrons from polarized top quark decay in the general two Higgs doublet model
• Azimuthal polarization of polarized top quark in noncommutative standard model
• QCD analysis of light charged Higgs production through polarized top quark decay in two various frames
• Charged Higgs production from polarized top-quark decay in the 2HDM considering the general-mass variable-flavor-number scheme