Observation of a Bc*+ meson with the ATLAS detector
Abstract
The first observation of a new meson state decaying into Bc+ and a photon is presented using a dataset of pp collisions at a centre-of-mass energy √s = 13\,\TeV collected by the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 140\,fb−1. The Bc+ mesons are reconstructed from a three-muon final state from Bc+→ J/ψ(μ+μ-)μ+νμX decays, along with photons reconstructed via conversions to electron-positron pairs in the detector material. The new state is observed with a significance that exceeds 8 standard deviations. The mass difference between the new meson state and the ground-state Bc+ meson is measured to be 64.5 ± 1.4(stat.)+1.0−1.4(syst.) MeV. This corresponds to a mass for the observed state of 6339.0 ± 1.4(stat.)+1.0−1.4(syst.)± 0.3 (mBc+) MeV, where the last uncertainty is due to the precision of the best knowledge of the Bc+ meson mass. The low mass difference value matches the theory expectations for the lowest vector state of the b̅c system, the Bc*+ meson.
Versions
Related
- Observation of single top-quark production in the s-channel in proton--proton collisions at √s=13 TeV with the ATLAS detector
- Measurement of forward jet suppression in Pb+Pb collisions at √(sNN)=5.02$ TeV with the ATLAS detector
- Measurement of tZq inclusive and differential cross-sections in pp collisions at √s = 13 TeV with the ATLAS detector
- 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
- Measurement of the Higgs boson decay to a low-mass dilepton system and a photon in pp collisions at √s = 13 and 13.6 TeV with the ATLAS detector
BibTeX
@misc{collaboration2026observation,
title = {{Observation of a $B_c^*+$ meson with the ATLAS detector}},
author = {ATLAS Collaboration},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.16228},
eprint = {2605.16228},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.16228},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Observation of a B_c^*+ meson with the ATLAS detector
AU - ATLAS Collaboration
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2605.16228
UR - https://arxiv.org/abs/2605.16228
AB - The first observation of a new meson state decaying into B_c^+ and a photon is presented using a dataset of pp collisions at a centre-of-mass energy √s = 13\,\TeV collected by the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 140\,fb^−1. The B_c^+ mesons are reconstructed from a three-muon final state from B_c^+→ J/ψ(μ^+μ^-)μ^+ν_μX decays, along with photons reconstructed via conversions to electron-positron pairs in the detector material. The new state is observed with a significance that exceeds 8 standard deviations. The mass difference between the new meson state and the ground-state B_c^+ meson is measured to be 64.5 ± 1.4(stat.)^+1.0_−1.4(syst.) MeV. This corresponds to a mass for the observed state of 6339.0 ± 1.4(stat.)^+1.0_−1.4(syst.)± 0.3 (m_B_c^+) MeV, where the last uncertainty is due to the precision of the best knowledge of the B_c^+ meson mass. The low mass difference value matches the theory expectations for the lowest vector state of the b̅c system, the B_c^*+ meson.
ER -