A reinterpretation of four top quark (tttt) production is presented using the full Run 2 dataset recorded by the CMS experiment, corresponding to an integrated luminosity of 138/fb. The analysis targets BSM scenarios using the existing tttt production measurement, including constraints on effective field theory (EFT) operators, top-philic heavy resonances, and the top-Yukawa coupling. The...
Effective Field Theory (EFT) provides a universal framework for probing beyond the Standard Model physics at LHC scales. Recent advances in analysis techniques and increased dataset complexity have significantly enhanced the sensitivity of EFT studies. We present the latest results on EFT obtained using ttbar production by the CMS collaboration, probing interactions between the top quark and...
We present analytic expressions for the one-loop QCD helicity amplitudes contributing to top-quark pair production in association with a photon or a jet at the Large Hadron Collider (LHC), evaluated through $O(\epsilon^2)$ in the dimensional regularisation parameter, $\epsilon$. These amplitudes are required to construct the two-loop hard functions that enter the NNLO QCD computation. The...
Rare event classification in high-energy physics (HEP) plays a crucial role in probing physics beyond the Standard Model (BSM). Such processes serve as indirect searches for new physics by testing deviations from SM predictions in extreme kinematic regimes. The production of four top quarks in association with a ($W^-$) boson at $(\sqrt{s} = 13)$ $ TeV$ is an exceptionally rare SM process with...
We will report on an extensive survey of rare and exclusive few-body decays of the top quark, defined as those with branching fractions BR≲$10^{-5}$ and two or three final-state particles [1]. Such rare decays probe physics beyond the Standard Model (BSM), constitute a background for exotic decays into new BSM particles, and provide precise information on quantum chromodynamics factorization...
Recent results from the CMS experiment at the Large Hadron Collider indicate the presence of a top-quark pair bound state near the $t\bar{t}$ threshold region. We present a way to reconstruct a toponium state at the ttbar threshold region formed at the Large Hadron Collider using Recursive Jigsaw Reconstruction. We have considered the Non-Relativistic QCD based toponium model implemented in...
A search for the standard model Higgs boson decaying to a cc pair, produced in association with a tt pair (ttH) is presented. The search is performed with the full Run 2 dataset, corresponding to an integrated luminosity of 138/fb. Advanced machine learning techniques are employed for jet flavor identification and event classification. The H->bb decay is measured simultaneously. The...
We present the first analytic results of next-to-next-to-next-to-leading-order (N3LO) QCD corrections to the top-quark decay width. We focus on the dominant leading color contribution, which includes light-quark loops. At next-to-next-to-leading order (NNLO), this dominant contribution accounts for 95% of the total correction. By utilizing the optical theorem, the N3LO corrections are related...
The Future Circular Collider (FCC) programme provides unique opportunities for comprehensive and precise studies of top quark physics. At the FCC-ee, operating at and slightly above the top pair threshold, a precise measurement of the top quark mass with a statistical and systematic accuracy down to the MeV level can be achieved through a threshold scan. Furthermore, the FCC-ee run at 365 GeV...
The current MiNNLOPS technology enables next-to-next-to-leading order (NNLO) QCD predictions matched to parton showers (NNLO+PS) for heavy-quark pair production in arbitrary kinematics (QQF), within the POWHEG framework. Among QQF processes, Higgs production in association with a heavy-quark pair is particularly relevant for LHC phenomenology. In the case of ttH production, the main bottleneck...
We present the calculation of two-loop Feynman integrals contributing to NNLO QCD corrections to the production of a top-quark pair in association with a W boson at hadron colliders, in the leading colour approximation. This process constitutes a key signature at the Large Hadron Collider, and the precise prediction of its cross-section is imperative for comparisons with experimental data. In...
