Many models beyond the standard model predict the existence of vector-like quarks or other types of heavy resonances. Using proton-proton collision data at center-of-mass energies of 8 and 13 TeV, the ATLAS and CMS Collaborations have performed a multitude of searches for pair and singly produced vector-like quarks decaying to W, Z, or Higgs bosons. Heavy gauge and (pseudo)scalar resonances decaying to top quarks have been searched for as well. No evidence for any of these hypothetical particles has been found yet, and stringent exclusion limits are derived on their masses, cross sections and couplings in various models.
A set of measurements of top quark pair and single top quark production in association with standard model (SM) bosons performed by the CMS and ATLAS Collaborations is presented. The consistency of these results among themselves and with the SM prediction is discussed. The latest results on four top quark production are also shown.
This article presents a review of recent results on direct top quark mass measurements performed by the ATLAS and CMS collaborations on $pp$ collisions collected during Run 2 of the LHC at $\sqrt{s}=$13 TeV.
Machine learning is essential in many aspects of top-quark related physics in the ATLAS and CMS Collaborations. This work aims to give a brief overview over current applications in the two collaborations as well as on-going studies for future applications. Copyright 2023 CERN for the benefit of the ATLAS and CMS Collaborations. Reproduction of this article or parts of it is allowed as specified in the CC-BY-4.0 license
Recent results on top quark modelling and tuning are presented. In particular, the focus of this talk is on the studies on the definition and commissioning of the common Monte Carlo effort carried out by ATLAS and CMS within the LHCtopWG. An overview of current recommendations for modelling uncertainties is also presented.
Latest results on inclusive top-quark pair production cross-sections are presented using collision data collected by ATLAS and CMS experiments at the LHC. Inclusive and differential measurements of top-quark pair production cross-sections from ATLAS and CMS are presented in the resolved and boosted kinematic regions. The cross-sections are measured as a function of various kinematic observables of the top quarks, the jets and leptons of the event final state.
Searches for resonances in final states with leptons and photons have always been a powerful tool for discovery in high energy physics. We present here the latest results from the ATLAS and CMS experiments, based on up to 36.1 fb$^{-1}$ of 13 TeV proton-proton collisions produced at the Large Hadron Collider. Detailed results on single lepton, dilepton, diphoton and Z$γ$ resonances are included.
Selected results from searches for new physics with unconventional signatures using the ATLAS and CMS detectors are presented. Such signatures include emerging jets, heavy charged particles, displaced or delayed objects, and disappearing tracks. These signatures may arise from hidden sectors or supersymmetric models. The searches use proton-proton collision data from Run 2 of the LHC with a center-of-mass energy of 13 TeV.
The production of top quarks through single or rare production modes has become important due to the large amount of data collected by both ATLAS and CMS at the LHC. Many searches are now studying these processes either as a targeted signal or as an important source of background. This document reviews the Monte Carlo simulations used to model these processes in ATLAS and CMS, and how the modeling systematic uncertainties are estimated. Many analyses have also recently released a large variety of unfolded distributions. These distributions are shown and the modeling from various Monte Carlo ge…
We present recent measurements of the top quark mass by the ATLAS and CMS experiments in the $\mathrm{t}\overline{\mathrm{t}}$ lepton+jets, all-hadronic, and dilepton channels. In addition, we present a measurement using a topology enriched in t-channel single top events. The analyses include observables whose sensitivity to the top mass is calibrated using Monte Carlo simulation before they are utilized to extract the value of $\mathrm{m}_{\mathrm{t}}$ in data. The measurements outlined here enter into recent combinations by ATLAS and CMS that yield a sub-GeV precision on the top mass.
Selected results of searches for neutral long-lived particles with displaced and delayed jets, trackless jets and emerging jets, as well as displaced muons, obtained with data recorded at a centre-of-mass energy of 13 TeV by the ATLAS and CMS Collaborations during LHC's Run 2 are presented, as well as challenges and techniques.
The production of single top quarks allows to study the interplay of top quark physics and the electroweak sector of the standard model. Deviations from predictions can be a hint for physics beyond the standard model. The t-channel is the dominant production mode for single top quarks at the LHC. This talk presents the latest measurements from the ATLAS and CMS collaborations.
The ATLAS and CMS Collaborations have performed a variety of measurements of the top quark mass, taking advantage of the abundant production of top quarks at the LHC. The most recent measurements are reported here, based on data collected at 8 and 13 TeV, with particular emphasis on the distinction between the so-called "direct" measurements and the "indirect" evaluations obtained from cross sections and differential cross sections.
Recent inclusive and differential cross section measurements of the associated production of top quark pairs with gauge bosons or heavy-flavor jets are reported. A search for physics beyond the standard model in the top quark sector is also presented. All measurements are based on data samples of proton-proton collisions at $\sqrt{s}=13$ TeV collected by the ATLAS and CMS experiments at the CERN LHC. No significant deviation from the standard model predictions is observed.
Top quarks are produced copiously at the LHC, and a variety of related measurements has been made in the recent years by the two collaborations ATLAS and CMS. The most recent measurements of the top quark mass by the two collaborations are reported here. The top quark mass has been measured with a relative uncertainty smaller than 0.3%, making the top quark the most accurately measured quark.
The latest results of high mass searches for new physics in a variety of final states from the CMS and ATLAS collaborations are presented. These searches are based on $\sqrt{s}=13$ TeV proton-proton collisions data at the LHC collected in the year 2016 and 2015. No excess above expectation from Standard Model processes are observed and exclusion limits are set at the 95% confidence level on various benchmark models.
The top-quark mass measurements carried out by the LHC experiments, ATLAS and CMS, are summarized. Results of different approaches to the top-quark mass reconstruction are presented. Masses from different measurements are in good agreement within uncertainties. Precision of the measurements with the directly measured top-quark mass is now better than 0.5%. Progress in determination of the top-quark pole mass is reported and the relation between the directly measured top-quark mass and top-quark pole mass is discussed.
Events containing a pair of high energy hadronic jet can provide clear signatures in the search for new physics at high energy hadron colliders. The ATLAS and CMS experiments collected the data from LHC collisions at $\sqrt{s}$= 13 TeV during 2015 and 2016, looking for evidence of new resonances or deviations from the Standard Model predictions. Althoug no hint of new physics was seen, strong limits have been set on the most interesting benchmark models, improving LHC Run1 reach.
Analyses of single top-quark production via $tW$ production, via $tZq$ production, and in the $s$-channel are presented, showing the scope of recent ATLAS and CMS analyses of $pp$ collisions produced at the LHC at $\sqrt{s}=7,8$, and ${13}\,\text{TeV}$. Cross-section values and signal significance estimates are established, confirming good agreement with the most precise available fixed-order calculations for each production mode.
We present results on the search for a light charged Higgs boson that can be produced in the decay of a top quark and later decays into a charm and an antistrange quark. The analysis is performed using $19.7\invfb$ pp collison data recorded with the CMS detector at LHC.
The phase $Φ_s$ is the key parameter for the CP-violation of the $B^0_s$-$\bar{B^0_s}$ system. An angular and proper decay time analysis is applied to the $B^0_s \rightarrow J/ψΦ$ events. Using a data sample collected by the CMS and ATLAS experiments in LHC Run1, the $B^0_s$ signal candidates are reconstructed and are used to extract the phase $Φ_s$. We present the latest update on the results in this decay channel.
These proceedings report on lepton and photon performance results obtained using data recorded in 2015 and 2016 at the LHC by the two experiments ATLAS and CMS. For each particle (electrons, photons and muons), the reconstruction and identification efficiencies are presented for the two experiments together with the isolation studies. Results concerning the electron and photon energy calibration as well as the muon momentum scale and resolution are also reported. Despite more challenging pile-up conditions with respect to Run 1, the two experiments achieved impressive performance in early Run …
An overview of recent searches with top quarks in the final state using up to 36 fb$^{-1}$ of pp collision data at $\sqrt{s}$ = 13 TeV collected with the ATLAS and CMS experiments at the LHC is presented. In particular, searches for heavy resonances decaying into third generation quarks, searches for production of vector-like quarks and searches for dark-matter produced in association with top quarks are summarised. No significant excess over the SM prediction is found and 95% CL exclusion limits are set in a variety of models.
Several electroweak precision measurements are performed by the ATLAS and CMS collaborations at the LHC. The main ones are carried out using Drell-Yan production of single W and Z boson. They regard the measurement of the production cross sections of W and Z bosons, the mass of the W boson, and $\sin^2θ_W$. The results of the $\sin^2θ_W$ measurements have an accuracy of approximately twice that reached at LEP and SLD. Other measurements reported are about the Drell-Yan differential production cross section.
An overview of the boosted top production analyses using data collected by the ATLAS and CMS experiments at $\sqrt{s}=$ 8 TeV and 13 TeV of proton-proton collisions at the LHC is presented. These analyses use techniques for the reconstruction of boosted objects to measure the production of top quarks at high transverse momenta. The measurements are optimized for the different final states and for different ranges of the transverse momenta of the particles involved, improving on measurements with traditional objects reconstruction based on the combination of resolved objects.
Searches for high-mass resonances decaying to pairs of standard model bosons using ATLAS and CMS detectors are presented. The searches use 15 - 36 $\textrm{fb}^{-1}$ of proton-proton collision data collected at the centre-of-mass energy of 13 TeV at the LHC. Many different final states have been considered and the results are interpreted in a range of theories beyond the standard model of particle physics, most common being heavy vector triplet and warped extra dimensions.
