Abstract

Using the helicity amplitude technique, we derive differential decay widths and angular distributions for the decay cascade $D\to K_{1}(1270,1400)\ell^+\nu_{\ell}\to (K\pi\pi)\ell^+\nu_{\ell} (\ell=e,\mu)$, in which the electron and muon mass is explicitly included. Using a set of phenomenological results for $D\to K_1$ form factors, we calculate partial decay widths and branching fractions for $D^0\to K_1^-\ell^+\nu_{\ell}$ and $D^+\to K_1^0\ell^+\nu_{\ell}$, but find that results for ${\cal B}(D\to K_1(1270)e^+\nu_{e})$ are larger than recent BESIII measurements by about a factor 1.5. We further demonstrate that the measurement of up-down asymmetry in $D\to K_{1}e^+\nu_e\to (K\pi\pi)e^+\nu_{e}$ and angular distributions in $D\to K_{1}\ell^+\nu_\ell\to (K\pi\pi)\ell^+\nu_{\ell}$ can help to determine the hadronic amplitude requested in $B\to K_1(\to K\pi\pi)\gamma$. Based on the Monte-Carlo simulation with the LHCb geometrical acceptance, we find that the angular distributions of MC events can be well described.

Highlights

  • Nowadays searching for new physics (NP) beyond the standard model (SM) is a most primary objective in particle physics

  • We further demonstrate that the measurement of up-down asymmetry in D → K1eþνe → ðKππÞeþνe and angular distributions in D → K1lþνl → ðKππÞlþνl can help to determine the hadronic amplitude requested in

  • Weak decays of heavy quarks have played an important role in testing standard model and probing new physics beyond

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Summary

Introduction

Nowadays searching for new physics (NP) beyond the standard model (SM) is a most primary objective in particle physics. This can in principle proceed in two distinct directions. The NP particles can affect various low-energy observables by modifying the coupling strength or introducing new interaction forms and a high precision study of these observables is likely to indirectly access the NP. In the SM, the charged weak interaction has the V − A chirality and thereby the photon in b → sγ is predominantly left-handed. A representative scenario of this type is the left-right symmetric model [4,5], in which the photon can acquire a significant right-handed component

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