Abstract
In this work, we investigate the prompt $J/\psi$ production in associated with top quark pair to leading order in the nonrelativistic QCD factorization formalism at the LHC with $\sqrt{s} =13$ TeV. In addition to the contribution from direct $J/\psi$ production, we also include the indirect contribution from the directly produced heavier charmmonia $\chi_{cJ}$ and $\psi^\prime$. We present the numerical results for the total and differential cross sections and find that the $\sideset{^3}{^{(8)}_1}{\mathop{{S}}}$ states give the dominant contributions. The prompt $t\bar t J/\psi$ signatures at the LHC are analyzed in the tetralepton channel $pp\to (t\to W^+(\ell^+\nu)b) (\bar t \to W^-(\ell^- \bar \nu)\bar b) (J/\psi\to\mu^+\mu^-)$ and trilepton channel $pp\to (t\to W(q q^\prime)b) ( t \to W(\ell \nu) b) (J/\psi\to\mu^+\mu^-)$, with the $J/\psi$ mesons decaying into muon pair, and the top quarks decaying leptonically or hadronically. We find that $t\bar t J/\psi$ proudction can be potentially detected at the LHC, whose measurement is useful to test the heavy quarkonium production mechanism.
Highlights
The nonrelativistic QCD (NRQCD) [1] provides a rigorous theory to study heavy-quarkonium physics, where the production cross section and decay rates can be divided into short-distance and long-distance parts
We investigate the prompt J=ψ production in associated with top quark pair to LO in the NRQCD factorization formalism at the 13 TeV LHC
The contributions for the indirect J=ψ production come from radiative decays of χcJ → J=ψ þ γ or hadronic decays of ψ0 → J=ψ þ X
Summary
The nonrelativistic QCD (NRQCD) [1] provides a rigorous theory to study heavy-quarkonium physics, where the production cross section and decay rates can be divided into short-distance and long-distance parts. The charmonium J=ψ associated-production channels are very important to test the heavy quarkonium physics. We plan to study the prompt J=ψ þ tt production at the LHC in the NRQCD factorization formalism to leading-order (LO). Contributions to the total ttJ=ψ production rate can come from the process of tt þ b-hadrons with weak decays of b → J=ψ þ X, which can be separated in the detectors.
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