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

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 $g^{\ast }\in [0.20,0.50]$ and $m_T$ up to 4 TeV are discoverable via the hadronic channel with MLP, and regions with $g^{\ast }\in [0.10,0.50]$ 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.

Comments: 33 pages,11 figures, 13 tables