Searches for vector-like quarks at CMS

The CMS Collaboration has a robust program of searches for vector-like quarks. The first search available using 137 fb$^{-1}$ of proton-proton collision data with $\sqrt{s} = 13$ TeV collected by the CMS experiment in Run 2 of the LHC is presented here. This search targets vector-like B quarks that decay to bH or bZ combinations in a hadronic final state. Lower limits on the mass of the B quark are determined for several branching fraction hypothesis, extending CMS sensitivity to these particles by 300 -- 500 GeV, depending on the decay mode

Measurement of the W boson helicity using top pair events at s\sqrt{s} = 8 TeV with the CMS detector

This document gives an overview over the recent results on helicity measurement of W boson originated from top pair events. The results are obtained using data collected by the CMS detector at a center-of-mass energy of 8 TeV. The helicity measurements are confronted with the most precise theoretical predictions of the standard model

Femtoscopy in sNN=5.02\sqrt{s_{\mathrm{NN}}} = 5.02 TeV pp-Pb collisions with \it{ATLAS}

Bose-Einstein correlations between identified charged pions are measured for $p$+Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV with the ATLAS detector using a total integrated luminosity of 28 nb$^{-1}$. Pions are identified using ionisation energy loss measured in the pixel detector. Two-particle correlation functions and the extracted source radii are presented as a function of average transverse pair momentum ($k_\mathrm{T}$) and rapidity ($y_{\pi\pi}^\star$) as well as collision centrality. Pairs are selected with a rapidity $-2 -1$ in the most central events

ttˉ{\rm t\bar{t}} cross section measurements in CMS

An overview of the most recent measurements of inclusive top quark pair production cross section is presented. The results are obtained using data collected with the CMS experiment in proton-proton collisions at centre-of-mass energies of 5.02, 7, 8 and 13 TeV. The data are compared with the predictions from perturbative QCD calculations at full NNLO+NNLL accuracy.An overview of the most recent measurements of inclusive top quark pair production cross section is presented. The results are obtained using data collected with the CMS experiment in proton-proton collisions at centre-of-mass energies of 5.02, 7, 8 and 13 TeV. The data are compared with the predictions from perturbative QCD calculations at full NNLO+NNLL accuracy

Why stop at two tops? Search for exotic production of top quarks in final states with same-sign leptons and bb-jets at 13 TeV

An analysis is presented of events containing jets including at least one $b$-tagged jet, sizable missing transverse momentum, and at least two charged leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. Standard Model processes rarely produce these final states, but several models of physics beyond the Standard Model predict an enhanced production rate of such events. Specific models with this feature are considered here: vector-like $T$, $B$, and $T_{5/3}$ quark pair production, and four top quark production under three scenarios (Standard Model, contact interaction, and extra-dimensions). A data sample of 3.2 fb$^{-1}$ of $pp$ collisions at a center-of-mass energy of $\sqrt{s}$=13 TeV recorded by the ATLAS detector at the Large Hadron Collider is used in this analysis. Several signal regions are defined, in which the consistency between the data yield and the background-only hypothesis is checked, and 95% confidence level limits are set on various signal models. The focus here is on models yielding signatures with four top quarks.An analysis is presented of events containing jets including at least one $b$-tagged jet, sizable missing transverse momentum, and at least two charged leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. Standard Model processes rarely produce these final states, but several models of physics beyond the Standard Model predict an enhanced production rate of such events. Specific models with this feature are considered here: vector-like $T$, $B$, and $T_{5/3}$ quark pair production, and four top quark production under three scenarios (Standard Model, contact interaction, and extra-dimensions). A data sample of 3.2 fb$^{-1}$ of $pp$ collisions at a center-of-mass energy of $\sqrt{s}$=13 TeV recorded by the ATLAS detector at the Large Hadron Collider is used in this analysis. Several signal regions are defined, in which the consistency between the data yield and the background-only hypothesis is checked, and 95% confidence level limits are set on various signal models. The focus here is on models yielding signatures with four top quarks

ttˉ+Vt\bar{t}+V production in ATLAS

The latest ATLAS results for processes with a top quark pair and an associated vector boson are presented here. The measurement of the production cross sections for these processes is important for the direct determination of the top quark couplings to gauge bosons and for constraints on new physics models, in particular for models which go beyond the Standard Model regarding the mechanism for the mass generation

Single Top Quark Production Measurements in CMS

The CMS experiment has measured the electroweak production of top quark in different singly production modes: t-, tW- and s-channel. Recent results on inclusive and differential cross section measurements of t-channel at 13 TeV and of the fiducial cross section at 8 TeV are shown. The search for single top quark production in s-channel at 7 and 8 TeV as well as the search for associated production of Z boson and single top are presented. All measurements are in agreement with the Standard Model prediction and no sign of new physics is observed.The CMS experiment has measured the electroweak production of top quark in different singly production modes: t-, tW- and s-channel. Recent results on inclusive and differential cross section measurements of t-channel at 13 TeV and of the fiducial cross section at 8 TeV are shown. The search for single top quark production in s-channel at 7 and 8 TeV as well as the search for associated production of Z boson and single top are presented. All measurements are in agreement with the Standard Model prediction and no sign of new physics is observed

Differential ttˉt\bar{t} Cross Section Measurements as a Function of Variables other than Kinematics

An overview of cross section measurements as a function of jet multiplicities and jet kinematics in association with $t\bar{t}$ production is presented. Both the ATLAS and the CMS collaborations performed a large number of measurements at different center-of-mass energies of the LHC using various $t\bar{t}$ decay channels. Theoretical predictions of these quantities usually rely on parton shower simulations that strongly depends on tunable parameters and come with large uncertainties. The measurements are compared to various theoretical descriptions based on different combinations of matrix-element calculations and parton-shower models.An overview of cross section measurements as a function of jet multiplicities and jet kinematics in association with $t\bar{t}$ production is presented. Both the ATLAS and the CMS collaborations performed a large number of measurements at different center-of-mass energies of the LHC using various $t\bar{t}$ decay channels. Theoretical predictions of these quantities usually rely on parton shower simulations that strongly depends on tunable parameters and come with large uncertainties. The measurements are compared to various theoretical descriptions based on different combinations of matrix-element calculations and parton-shower models