Probing Light Scalars and Vector-like Quarks at the High-Luminosity LHC

Abstract

A model based on a $U(1{)}_{T_R^3}$ extension of the Standard Model can address the mass hierarchy between generations of fermions, explain thermal dark matter abundance, and the muon $g-2$, $R_{(D)}$, and $R_{(D^{\ast })}$ anomalies. The model contains a light scalar boson ${\varphi }^{\prime }$ and a heavy vector-like quark ${\chi }_{\mathrm{u}}$ that can be probed at CERN's Large Hadron Collider (LHC). We perform a phenomenology study on the production of ${\varphi }^{\prime }$ and ${\chi }_u$ particles from proton-proton $(\mathrm{pp})$ collisions at the LHC at $\sqrt{s}=13.6$ TeV, primarily through $g-g$ and $t-{\chi }_{\mathrm{u}}$ fusion. We work under an effective field theory approach, in which the ${\chi }_{\mathrm{u}}$ and ${\varphi }^{\prime }$ masses are free parameters. We perform a phenomenological analysis considering ${\chi }_{\mathrm{u}}$ final states to b-quarks, muons, and neutrinos, and ${\varphi }^{\prime }$ decays to ${\mu }^{+}{\mu }^{-}$. A machine learning algorithm is used to maximize the signal sensitivity, considering an integrated luminosity of $3000$ ${\text{fb}}^{-1}$. The proposed methodology can be a key mode for discovery over a large mass range, including low masses, traditionally considered difficult due to experimental constraints.

References in corpus (31)

• PyTorch: An Imperative Style, High-Performance Deep Learning Library
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• MadAnalysis 5, a user-friendly framework for collider phenomenology
• 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
• 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
• High-pT Signatures in Vector-Leptoquark Models
• Measurement of $\mathcal{R}(D)$ and $\mathcal{R}(D^{\ast })$ with a semileptonic tagging method
• Performance of the reconstruction and identification of high-momentum muons in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Vector-like Singlet Quarks: a Roadmap
• Search for heavy neutrinos or third-generation leptoquarks in final states with two hadronically decaying tau leptons and two jets in proton-proton collisions at sqrt(s) = 13 TeV
• Search for heavy resonances decaying to tau lepton pairs in proton-proton collisions at sqrt(s) = 13 TeV
• Search for single production of a vector-like $T$ quark decaying into a Higgs boson and top quark with fully hadronic final states using the ATLAS detector
• Search for pair-production of vector-like quarks in $pp$ collision events at $\sqrt{s}=13$ TeV with at least one leptonically decaying $Z$ boson and a third-generation quark with the ATLAS detector
• Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector
• Roadmap to explore vectorlike quarks decaying to a new scalar or pseudoscalar
• Expanding the Reach of Heavy Neutrino Searches at the LHC
• Searching for New Heavy Neutral Gauge Bosons using Vector Boson Fusion Processes at the LHC
• Discovery prospects of a vectorlike top partner decaying to a singlet boson
• Search for single production of vector-like $T$ quarks decaying into $Ht$ or $Zt$ in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Machine learning-enhanced search for a vectorlike singlet $B$ quark decaying to a singlet scalar or pseudoscalar
• Dark matter in the Scotogenic model with spontaneous lepton number violation
• Probing Heavy Spin-2 Bosons with $\gamma \gamma$ final states from Vector Boson Fusion Processes at the LHC
• Search for singly produced vector-like top partners in multilepton final states with 139 ${\mathrm{fb}}^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV with the ATLAS detector
• Deeply Learned Preselection of Higgs Dijet Decays at Future Lepton Colliders
• Probing a ${\mathrm{Z}}^{\prime }$ with non-universal fermion couplings through top quark fusion, decays to bottom quarks, and machine learning techniques
• Probing an MeV-Scale Scalar Boson in Association with a TeV-Scale Top-Quark Partner at the LHC
• Probing highly collimated photon-jets with deep learning
• Improving heavy Dirac neutrino prospects at future hadron colliders using machine learning
• Searching for exclusive leptoquarks with the Nambu-Jona-Lasinio composite model at the LHC and HL-LHC
• Is the muon a third family lepton?

Cited by in corpus (1)

• Tagging fully hadronic exotic decays of the vectorlike $\mathbf{B}$ quark using a graph neural network