Measuring Vcb at electron-proton colliders
Abstract
We study the prospects for an independent determination of Vcb from bottom-tagged charged-current deep-inelastic scattering at future electron-proton colliders: the EIC, LHeC, and FCC-eh. The transition e- c → νe b probes |Vcb|2 through a process with different theoretical and experimental uncertainties from semileptonic B decays. We fit ratios of b-tagged charged-current event counts over flavour-inclusive ones in kinematic bins, including correlated parton-distribution and flavour-tag calibration uncertainties, and floating the other CKM parameters. With projected parton distributions and tagging performance motivated by existing studies, we find a potential relative sensitivity in |Vcb| of about 0.8% at the LHeC with 1 ab−1 of integrated luminosity and 0.7% at FCC-eh with 2 ab−1. The corresponding EIC sensitivity is instead at the level of 20 − 30 %, depending on the configuration. The LHeC could thus provide a high-energy determination competitive with low-energy ones, but with substantially different dominant systematic uncertainties, on the timescale of its proposed operation between the HL-LHC and FCC-ee. We identify precise flavour-tag calibration and control of the kinematic response as the main requirements for realising this potential sensitivity.
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BibTeX
@misc{marzocca2026measuring,
title = {{Measuring $V_cb$ at electron-proton colliders}},
author = {David Marzocca},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18961},
eprint = {2610.18961},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.18961},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Measuring V_cb at electron-proton colliders
AU - David Marzocca
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.18961
UR - https://arxiv.org/abs/2610.18961
AB - We study the prospects for an independent determination of V_cb from bottom-tagged charged-current deep-inelastic scattering at future electron-proton colliders: the EIC, LHeC, and FCC-eh. The transition e^- c → ν_e b probes |V_cb|^2 through a process with different theoretical and experimental uncertainties from semileptonic B decays. We fit ratios of b-tagged charged-current event counts over flavour-inclusive ones in kinematic bins, including correlated parton-distribution and flavour-tag calibration uncertainties, and floating the other CKM parameters. With projected parton distributions and tagging performance motivated by existing studies, we find a potential relative sensitivity in |V_cb| of about 0.8% at the LHeC with 1 ab^−1 of integrated luminosity and 0.7% at FCC-eh with 2 ab^−1. The corresponding EIC sensitivity is instead at the level of 20 − 30 %, depending on the configuration. The LHeC could thus provide a high-energy determination competitive with low-energy ones, but with substantially different dominant systematic uncertainties, on the timescale of its proposed operation between the HL-LHC and FCC-ee. We identify precise flavour-tag calibration and control of the kinematic response as the main requirements for realising this potential sensitivity.
ER -