Related papers: Down Type Isosinglet Quarks in ATLAS
The measurements of the top quark mass given are obtained from ATLAS data taken at proton--proton centre-of-mass energies of $\sqrt{s}=7$ and $8$ TeV. An extraction of the top quark pole mass ($m_{\mathrm{top}}^{\mathrm{pole}}$) at…
An inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in $pp$ collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron Collider, have been…
The top quark mass measurement with ATLAS in the lepton plus jets channel is summarized from the perspective of the early data. Using the invariant mass of the three jets arising from the hadronic side as the estimator of the top quark…
A measurement of jet shapes in top-quark pair events using 1.8 fb(-1) of sqrt(s) = 7 TeV pp collision data recorded by the ATLAS detector at the LHC is presented. Samples of top-quark pair events are selected in both the single-lepton and…
Searches for dijet resonances with sub-TeV masses using the ATLAS detector at the Large Hadron Collider can be statistically limited by the bandwidth available to inclusive single-jet triggers, whose data-collection rates at low transverse…
Long-lived particles are contained in a variety of beyond Standard Model theories, including supersymmetric models, universal extra dimensions, or technicolor theories. If the lifetime of such a particle is long enough, the particle can…
A search for pair production of up-type vector-like quarks ($T$) with a significant branching ratio into a top quark and either a Standard Model Higgs boson or a $Z$ boson is presented. The same analysis is also used to search for…
Dijet events produced in LHC proton--proton collisions at a center-of-mass energy $\sqrt{s}=8$ TeV are studied with the ATLAS detector using the full 2012 data set, with an integrated luminosity of 20.3 fb$^{-1}$. Dijet masses up to about…
A measurement of the top quark mass in topologies enhanced with single top quarks produced in the $t$-channel produced via weak interactions is presented. The dataset was collected at a centre-of-mass energy of $\sqrt{s}=8\,\mathrm{TeV}$…
We investigate the physics case for a dedicated trigger-level analysis for very low mass diphoton resonances at ATLAS and CMS and introduce a new photon isolation criterion. This greatly increases the acceptance for light particles at the…
A search is presented for single production of a vector-like $B$ quark decaying into a Standard Model $b$-quark and a Standard Model Higgs boson, which decays into a $b\bar{b}$ pair. The search is carried out in 139 fb$^{-1}$ of $\sqrt{s} =…
Heavy vector-like quarks of charge $-1/3$, $B$, have been searched for at the LHC through the decays $B\rightarrow bZ,\, bh,\,tW$. In models where the $B$ quark also carries charge under a new gauge group, new decay channels may dominate.…
Searches for a scalar top quark and a scalar bottom quark have been performed using a total data sample of 56.8 pb-1 at a centre-of-mass energy of 183 GeV collected with the OPAL detector at LEP. No candidate events were observed. Combining…
Measurements of the top--antitop quark pair production charge asymmetry in the dilepton channel, characterized by two high-${p}_{\rm{T}}$ leptons (electrons or muons), are presented using data corresponding to an integrated luminosity of…
We analyse $\Delta C=2$ transitions in the framework of a minimal extension of the Standard Model where either a $Q=2/3$ or a $Q=-1/3$ isosinglet quark is added to the standard quark spectrum. In the case of a $Q=2/3$ isosinglet quark, it…
A search for a heavy neutral Higgs boson, $A$, decaying into a $Z$ boson and another heavy Higgs boson, $H$, is performed using a data sample corresponding to an integrated luminosity of 139 fb$^{-1}$ from proton-proton collisions at…
A search for leptoquarks decaying into the $b\tau$ final state is performed using Run 2 proton-proton collision data from the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$ at $\sqrt{s} = 13$ TeV recorded…
We present a search for hypothetical vector-like quarks in ppbar collisions at sqrt(s) = 1.96 TeV. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb^(-1). We…
A search for new physics is presented in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from b quarks, and missing transverse momentum ($p_\mathrm{T}^\text{miss}$). The search uses…
The top-quark mass is measured in the all-hadronic top-antitop quark decay channel using proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. The data set used…