Search for Vector-Like Singlet Top ($T$) Quark in a Future Muon-Proton ($\mu p$) Collider at $\sqrt{s} = 5.29, 6.48,$ and $9.16$ TeV using Advanced Machine Learning Architectures

TL;DR

This study assesses the discovery potential of vector-like top quarks at future muon-proton colliders using advanced machine learning techniques, demonstrating significant sensitivity across various energies and decay channels.

Contribution

It introduces a comprehensive analysis employing multivariate classifiers to optimize detection of vector-like top quarks at future muon-proton colliders, exploring multiple decay channels and energy configurations.

Findings

9.16 TeV collider can discover top quarks up to 4 TeV with 100 fb$^{-1}$.

Hadronic channels outperform at intermediate masses, leptonic channels are more robust at higher masses.

High luminosity enables probing of new physics with significant sensitivity to coupling strengths.

Abstract

In this work, we explore the discovery potential of Vector-Like Singlet Top quarks ($T$) at a future $\mu p$ collider with center-of-mass energies of 5.29, 6.48, and 9.16 TeV, providing a unique environment to probe beyond Standard Model limits. We analyze the $T \to Wb$ decay mode in both fully hadronic ($bjj$) and leptonic ($bl\nu$) final states, offering a multi-channel assessment of $T$-quark sensitivity across a mass range of 2 to 5 TeV. Our methodology employs multivariate classifiers such as Boosted Decision Trees (BDTs) and Multi-Layer Perceptrons (MLP) to optimize signal-to-background discrimination in complex final states. The results demonstrate that the 9.16 TeV benchmark acts as a definitive discovery machine; even with 100 fb$^{-1}$ of data, the statistical significance exceeds $5\sigma$ up to 4 TeV masses. We identify a crossover effect where hadronic channels provide superior reach at intermediate masses due to higher branching ratios, while leptonic channels offer robustness at 5 TeV where purity limits detection. Incorporating a 20\% systematic uncertainty via Asimov significance ($Z_A$), we quantify the transition from fluctuation-dominated to systematic-dominated regimes at high luminosities. At 3000 fb$^{-1}$, regions with $g^{*} \in [0.20, 0.50]$ and $m_T$ up to 4 TeV are discoverable via the hadronic channel with MLP, and regions with $g^{*} \in [0.10, 0.50]$ and $m_T$ up to 5 TeV are accessible through the leptonic channel with BDT, highlighting the collider's potential to probe new physics beyond the Standard Model.