Probing in single-top production at colliders

Edier Paredes Cruz; Antonio O. Bouzas; F. Larios

doi:10.1140/epjp/s13360-025-06050-4

EPJ

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2023 Impact factor 2.8

EPJ PLUS - Condensed Matter and Complex Systems

Open Access

Eur. Phys. J. Plus (2025) 140: 130
https://doi.org/10.1140/epjp/s13360-025-06050-4

Regular Article

Probing $| V_{td} |$ $|V_{td}|$ in single-top production at $p e^{\mp}$ $pe^{\mp }$ colliders

Edier Paredes Cruz, Antonio O. Bouzas^a and F. Larios

Departamento de Física Aplicada, CINVESTAV-IPN, Carretera Antigua a Progreso Km. 6, Apdo. Postal 73 “Cordemex”, 97310, Mérida, Yucatán, Mexico

^a abouzas@cinvestav.mx

Received: 27 May 2024
Accepted: 22 January 2025
Published online: 15 February 2025

Abstract

We study the consequences for top-quark physics of having electron and positron beams available at the LHeC and FCC-he, as was the case in HERA. We show that the asymmetry between top production in $p e^{+}$ $$pe^+$$ collisions and antitop production in $p e^{-}$ $$pe^-$$ reactions is sensitive to $| V_{td} |$ $|V_{td}|$ . By means of detailed parton-level Monte Carlo simulations of single t and $\bar{t}$ $\bar{t}$ production and its backgrounds, we parametrize the asymmetry dependence on $| V_{td} |$ $|V_{td}|$ and estimate its uncertainties. Our analysis includes realistic phase-space cuts and machine-learning binary classifiers for background rejection. We thus obtain limits on $| V_{td} |$ $|V_{td}|$ that are substantially stronger than current ones and also smaller than current projections for the HL-LHC. We have $| V_{td} | < 1.6 \times | V_{td}^{PDG} |$ $|V_{td}| < 1.6\times |V_{td}^{\textrm{PDG}}|$ at the LHeC, at 68% C.L. with $L_{int} = 2$ $L_{\textrm{int}}=2$ /ab.

© The Author(s) 2025

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