A Search in LHCb Open Data for f-Baryon Resonances Predicted at HADRON 2025
Abstract
A prediction presented at HADRON 2025 proposed two baryon-like states containing an additional hypothesized f quark that could appear in the decay Bbar→LbLc K- in the form of narrow Lc K- resonances at 3800 and 3950~MeV. Public LHCb data are used here to compare three hypotheses with an unbinned, background-aware two-dimensional Dalitz likelihood. The baseline contains nonresonant three-body phase space and an N(1900) contribution in Lb K-. A second model tests the two a-priori prediction masses directly, fixing Lc K- resonances at 3800 and 3950~MeV while fitting their widths. A third model keeps the 3800-MeV mass fixed, allows the second Lc K- mass and width to float, and adds two exotic LcLb contributions. The second model gives a nominal Wilks-equivalent improvement of 4.02σ over the baseline, while the third gives a nominal value of 6.17σ. The quoted significances are model-comparison diagnostics only: the resonance fractions are constrained to be non-negative, some fitted widths reach parameter boundaries, the floating mass introduces a trials effect, and efficiency and systematic uncertainties are not yet incorporated.
Related
- Measurements of time-dependent b-hadron properties in LHCb
- Probing Υ(1S), ηb and hb resonances in proton-lead collisions at the LHCb
- Observation of the Doubly Charmed Baryon Ξ c c + with the LHCb Run 3 Detector
- Search for low-mass resonances decaying to ττ in proton-proton collisions at √s = 13.6 TeV
- Search for high-mass resonances in photon-jet final states using 140 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector
BibTeX
@misc{chapman2026search,
title = {{A Search in LHCb Open Data for $f$-Baryon Resonances Predicted at HADRON 2025}},
author = {Soctt Chapman},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37674},
eprint = {2610.37674},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37674},
}
RIS
TY - UNPB
TI - A Search in LHCb Open Data for f-Baryon Resonances Predicted at HADRON 2025
AU - Soctt Chapman
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.37674
UR - https://arxiv.org/abs/2610.37674
AB - A prediction presented at HADRON 2025 proposed two baryon-like states containing an additional hypothesized f quark that could appear in the decay Bbar→LbLc K^- in the form of narrow Lc K^- resonances at 3800 and 3950~MeV. Public LHCb data are used here to compare three hypotheses with an unbinned, background-aware two-dimensional Dalitz likelihood. The baseline contains nonresonant three-body phase space and an N(1900) contribution in Lb K^-. A second model tests the two a-priori prediction masses directly, fixing Lc K^- resonances at 3800 and 3950~MeV while fitting their widths. A third model keeps the 3800-MeV mass fixed, allows the second Lc K^- mass and width to float, and adds two exotic LcLb contributions. The second model gives a nominal Wilks-equivalent improvement of 4.02σ over the baseline, while the third gives a nominal value of 6.17σ. The quoted significances are model-comparison diagnostics only: the resonance fractions are constrained to be non-negative, some fitted widths reach parameter boundaries, the floating mass introduces a trials effect, and efficiency and systematic uncertainties are not yet incorporated.
ER -