In this section
@article{Collaboration:2025:1361-6633/adf7d3,
author = {Collaboration, TC},
doi = {1361-6633/adf7d3},
journal = {Rep Prog Phys},
title = {Observation of a pseudoscalar excess at the top quark pair production threshold.},
url = {http://dx.doi.org/10.1088/1361-6633/adf7d3},
volume = {88},
year = {2025}
}
TY - JOUR
AB - A search for resonances in top quark pair (tt-) production in final states with two charged leptons and multiple jets is presented, based on proton-proton collision data collected by the CMS experiment at the CERN LHC ats=13TeV, corresponding to 138 fb-1. The analysis explores the invariant mass of thett-system and two angular observables that provide direct access to the correlation of top quark and antiquark spins. A significant excess of events is observed near the kinematictt-threshold compared to the non-resonant production predicted by fixed-order perturbative quantum chromodynamics (pQCD). The observed enhancement is consistent with the production of a color-singlet pseudoscalar (1S0[1]) quasi-bound toponium state, as predicted by non-relativistic quantum chromodynamics. Using a simplified model for1S0[1]toponium, the cross section of the excess above the pQCD prediction is measured to be8.8-1.4+1.2pb.
AU - Collaboration,TC
DO - 1361-6633/adf7d3
PY - 2025///
TI - Observation of a pseudoscalar excess at the top quark pair production threshold.
T2 - Rep Prog Phys
UR - http://dx.doi.org/10.1088/1361-6633/adf7d3
UR - https://www.ncbi.nlm.nih.gov/pubmed/40763770
VL - 88
ER -