Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs ($t\bar{t}$) are measured using the full LHC Run 2 data sample collected with the ATLAS detector. The data were collected at a $pp$ collision energy of $\sqrt{s}=13$ TeV and correspond to an integrated luminosity of 140 fb$^{-1}$. The measurements use events containing an oppositely charged $e\mu$ pair and $b$-tagged jets. The results are compared with predictions from several Monte Carlo generators. While no prediction is found to be consistent with all distributions, a better agreement with measurements of the lepton $p_{\text{T}}$ distributions is obtained by reweighting the $t\bar{t}$ sample so as to reproduce the top-quark $p_{\text{T}}$ distribution from an NNLO calculation. The inclusive top-quark pair production cross-section is measured as well, both in a fiducial region and in the full phase-space. The total inclusive cross-section is found to be \[ \sigma_{t\bar{t}} = 829 \pm 1\;(\textrm{stat}) \pm 13\;(\textrm{syst}) \pm 8\;(\textrm{lumi}) \pm 2\; (\textrm{beam})\ \textrm{pb}, \] where the uncertainties are due to statistics, systematic effects, the integrated luminosity and the beam energy. This is in excellent agreement with the theoretical expectation.
Definition of the fiducial phase space with the lepton candidate, electron $e$ and muon $\mu$, and jets.
Breakdown of systematic uncertainties in the measured fiducial cross-section. The impact of the top-quark mass on the cross-section is included in the table and not counted in the total uncertainty entry in the paper.
Data bootstrap post unfolding for the fiducial cross-section. The replicas are obtained by reweighting each observed data event by a random integer generated according to Poisson statistics, using the BootstrapGenerator software package (https://gitlab.cern.ch/atlas-physics/sm/StandardModelTools_BootstrapGenerator/BootstrapGenerator), which implements a technique described in ATL-PHYS-PUB-2021-011 (https://cds.cern.ch/record/2759945). The ATLAS event number and run number of each event are used as seed to uniquely but reproducibly initialise the random number generator for each event. All the provided numbers originate from pseudo-data, including the 0th entry, and are in units of [fb].
This paper presents a search for dark matter, $\chi$, using events with a single top quark and an energetic $W$ boson. The analysis is based on proton-proton collision data collected with the ATLAS experiment at $\sqrt{s}=$ 13 TeV during LHC Run 2 (2015-2018), corresponding to an integrated luminosity of 139 fb$^{-1}$. The search considers final states with zero or one charged lepton (electron or muon), at least one $b$-jet and large missing transverse momentum. In addition, a result from a previous search considering two-charged-lepton final states is included in the interpretation of the results. The data are found to be in good agreement with the Standard Model predictions and the results are interpreted in terms of 95% confidence-level exclusion limits in the context of a class of dark matter models involving an extended two-Higgs-doublet sector together with a pseudoscalar mediator particle. The search is particularly sensitive to on-shell production of the charged Higgs boson state, $H^{\pm}$, arising from the two-Higgs-doublet mixing, and its semi-invisible decays via the mediator particle, $a$: $H^{\pm} \rightarrow W^\pm a (\rightarrow \chi\chi)$. Signal models with $H^{\pm}$ masses up to 1.5 TeV and $a$ masses up to 350 GeV are excluded assuming a tan$\beta$ value of 1. For masses of $a$ of 150 (250) GeV, tan$\beta$ values up to 2 are excluded for $H^{\pm}$ masses between 200 (400) GeV and 1.5 TeV. Signals with tan$\beta$ values between 20 and 30 are excluded for $H^{\pm}$ masses between 500 and 800 GeV.
<b>- - - - - - - - Overview of HEPData Record - - - - - - - -</b> <br><br> <b>Exclusion contours:</b> <ul> <li><a href="?table=highst_mamh_obs">Combined sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=highst_mamh_exp">Combined sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=highst_mhtb_lowma_obs">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=highst_mhtb_lowma_exp">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=highst_mhtb_highma_obs">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=highst_mhtb_highma_exp">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=lowst_mamh_obs">Combined sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=lowst_mamh_exp">Combined sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=lowst_mhtb_lowma_obs">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=lowst_mhtb_lowma_exp">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=lowst_mhtb_highma_obs">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=lowst_mhtb_highma_exp">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_mamh_obs">0L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_mamh_exp">0L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_mhtb_lowma_obs">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_mhtb_lowma_exp">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_mhtb_highma_obs">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_mhtb_highma_exp">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_mamh_obs">0L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_mamh_exp">0L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_mhtb_lowma_obs">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_mhtb_lowma_exp">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_mhtb_highma_obs">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_mhtb_highma_exp">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_mamh_obs">1L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_mamh_exp">1L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_mhtb_lowma_obs">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_mhtb_lowma_exp">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_mhtb_highma_obs">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_mhtb_highma_exp">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_mamh_obs">1L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=1LBoosted_lowst_mamh_exp">1L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_mhtb_lowma_obs">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=1LBoosted_lowst_mhtb_lowma_exp">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_mhtb_highma_exp">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_highst_mamh_obs">2L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=2L_highst_mamh_exp">2L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_highst_mhtb_lowma_obs">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=2L_highst_mhtb_lowma_exp">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_highst_mhtb_highma_obs">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Obs.)</a> <li><a href="?table=2L_highst_mhtb_highma_exp">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_lowst_mamh_exp">2L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_lowst_mhtb_lowma_exp">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=2L_lowst_mhtb_highma_exp">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW signals (Exp.)</a> <li><a href="?table=highst_dmtt_mamh_obs">Combined sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=highst_dmtt_mamh_exp">Combined sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=highst_dmtt_mhtb_lowma_obs">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=highst_dmtt_mhtb_lowma_exp">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=highst_dmtt_mhtb_highma_obs">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=highst_dmtt_mhtb_highma_exp">Combined sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=lowst_dmtt_mamh_obs">Combined sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=lowst_dmtt_mamh_exp">Combined sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=lowst_dmtt_mhtb_lowma_obs">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=lowst_dmtt_mhtb_lowma_exp">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=lowst_dmtt_mhtb_highma_obs">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=lowst_dmtt_mhtb_highma_exp">Combined sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mamh_obs">0L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mamh_exp">0L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mhtb_lowma_obs">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mhtb_lowma_exp">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mhtb_highma_obs">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_highst_dmtt_mhtb_highma_exp">0L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mamh_obs">0L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mamh_exp">0L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mhtb_lowma_obs">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mhtb_lowma_exp">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mhtb_highma_obs">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=0LBoosted_lowst_dmtt_mhtb_highma_exp">0L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mamh_obs">1L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mamh_exp">1L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mhtb_lowma_obs">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mhtb_lowma_exp">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mhtb_highma_obs">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_highst_dmtt_mhtb_highma_exp">1L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mamh_obs">1L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mamh_exp">1L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mhtb_lowma_obs">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mhtb_lowma_exp">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mhtb_highma_obs">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=1LBoosted_lowst_dmtt_mhtb_highma_exp">1L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_highst_dmtt_mamh_obs">2L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=2L_highst_dmtt_mamh_exp">2L channel sin$\theta$ = 0.7 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_highst_dmtt_mhtb_lowma_obs">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=2L_highst_dmtt_mhtb_lowma_exp">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_highst_dmtt_mhtb_highma_obs">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=2L_highst_dmtt_mhtb_highma_exp">2L channel sin$\theta$ = 0.7 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_lowst_dmtt_mamh_exp">2L channel sin$\theta$ = 0.35 $m_a$-$m_{H^{\pm}}$ exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_lowst_dmtt_mhtb_lowma_obs">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=2L_lowst_dmtt_mhtb_lowma_exp">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 150 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> <li><a href="?table=2L_lowst_dmtt_mhtb_highma_obs">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Obs.)</a> <li><a href="?table=2L_lowst_dmtt_mhtb_highma_exp">2L channel sin$\theta$ = 0.35 $m_{H^{\pm}}$-tan$\beta$ ($m_{a}$ = 250 GeV) exclusion contour using DMtW+DMtt signals (Exp.)</a> </ul> <b>Upper limits:</b> <ul> <li><a href="?table=mamH_xSecUpperLimit_Comb_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_Comb_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_Comb_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_Comb_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_Comb_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_Comb_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.7) cross-sections from combined (0L+1L+2L) fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_Comb_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_Comb_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_Comb_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_Comb_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_Comb_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_Comb_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.35) cross-sections from combined (0L+1L+2L) fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_0L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 0L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_0L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 0L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_0L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 0L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_0L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.7) cross-sections from 0L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_0L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.7) cross-sections from 0L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_0L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.7) cross-sections from 0L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_0L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 0L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_0L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 0L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_0L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 0L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_0L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.35) cross-sections from 0L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_0L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.35) cross-sections from 0L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_0L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.35) cross-sections from 0L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_1L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 1L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_1L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 1L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_1L_st0p7">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.7) cross-sections from 1L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_1L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.7) cross-sections from 1L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_1L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.7) cross-sections from 1L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_1L_st0p7_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.7) cross-sections from 1L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_1L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 1L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_1L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 1L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_1L_st0p35">Observed upper limit on the 2HDM+a tW+DM (sin$\theta$ = 0.35) cross-sections from 1L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mamH_xSecUpperLimit_1L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM(sin$\theta$ = 0.35) cross-sections from 1L individual fit in the $m_a$-$m_{H^{\pm}}$ plane.</a> <li><a href="?table=mHtblow_xSecUpperLimit_1L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM +tt+DM (sin$\theta$ = 0.35) cross-sections from 1L individual fit in the low $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> <li><a href="?table=mHtbhigh_xSecUpperLimit_1L_st0p35_DMtt">Observed upper limit on the 2HDM+a tW+DM + tt+DM (sin$\theta$ = 0.35) cross-sections from 1L individual fit in the high $m_a$ $m_{H^{\pm}}$-tan$\beta$ plane.</a> </ul> <b>Kinematic distributions:</b> <ul> <li><a href="?table=SR0L_mwtagged">0L region m(b1,W-tagged)</a> <li><a href="?table=SR0L_mtbmet">0L region m_{\mathrm{T}}^{\mathrm{b,E_{\mathrm{T}^{\mathrm{miss}}}}}</a> <li><a href="?table=SR0L_nwtagged">0L region N_{\mathrm{W-tagged}}</a> <li><a href="?table=SR1L_Had_mbj">1L hadronic top $m_{\mathrm{b1},\mathrm{\cancel{b1}}}$</a> <li><a href="?table=SR1L_Lep_mbj">1L leptonic top $m_{\mathrm{b1},\mathrm{\cancel{b1}}}$</a> <li><a href="?table=SR1L_Lep_nwtaggged">1L leptonic top region N_{\mathrm{W-tagged}}</a> </ul> <b>Cut flows:</b> <ul> <li><a href="?table=cutflow_SR0L">Cutflow of 4 signal points in the 0L regions.</a> <li><a href="?table=cutflow_SR1L_Had">Cutflow of 4 signal points in the 1L hadronic top regions.</a> <li><a href="?table=cutflow_SR1L_Lep">Cutflow of 4 signal points in the 1L leptonic top region.</a> </ul> <b>Acceptance and efficiencies:</b> <ul> <li> <b>highst_grid1_0L:</b> <a href="?table=highst_grid1_Acc_0L">Acceptance table of the 0L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <a href="?table=highst_grid1_Eff_0L">Efficiency table of the 0L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <li> <b>highst_grid2_0L:</b> <a href="?table=highst_grid2_Acc_0L">Acceptance table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <a href="?table=highst_grid2_Eff_0L">Efficiency table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <li> <b>highst_grid3_0L:</b> <a href="?table=highst_grid3_Acc_0L">Acceptance table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <a href="?table=highst_grid3_Eff_0L">Efficiency table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <li> <b>highst_grid1_1L:</b> <a href="?table=highst_grid1_Acc_1L">Acceptance table of the 1L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <a href="?table=highst_grid1_Eff_1L">Efficiency table of the 1L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <li> <b>highst_grid2_1L:</b> <a href="?table=highst_grid2_Acc_1L">Acceptance table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <a href="?table=highst_grid2_Eff_1L">Efficiency table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <li> <b>highst_grid3_1L:</b> <a href="?table=highst_grid3_Acc_1L">Acceptance table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <a href="?table=highst_grid3_Eff_1L">Efficiency table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.7, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <li> <b>lowst_grid1_0L:</b> <a href="?table=lowst_grid1_Acc_0L">Acceptance table of the 0L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <a href="?table=lowst_grid1_Eff_0L">Efficiency table of the 0L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <li> <b>lowst_grid2_0L:</b> <a href="?table=lowst_grid2_Acc_0L">Acceptance table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <a href="?table=lowst_grid2_Eff_0L">Efficiency table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <li> <b>lowst_grid3_0L:</b> <a href="?table=lowst_grid3_Acc_0L">Acceptance table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <a href="?table=lowst_grid3_Eff_0L">Efficiency table of the 0L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <li> <b>lowst_grid1_1L:</b> <a href="?table=lowst_grid1_Acc_1L">Acceptance table of the 1L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <a href="?table=lowst_grid1_Eff_1L">Efficiency table of the 1L SRs in the $m_a$-$m_{H^{\pm}}$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and tan$\beta$ = 1.</a> <li> <b>lowst_grid2_1L:</b> <a href="?table=lowst_grid2_Acc_1L">Acceptance table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <a href="?table=lowst_grid2_Eff_1L">Efficiency table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 150 GeV.</a> <li> <b>lowst_grid3_1L:</b> <a href="?table=lowst_grid3_Acc_1L">Acceptance table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> <a href="?table=lowst_grid3_Eff_1L">Efficiency table of the 1L SRs in the $m_{H^{\pm}}$-tan$\beta$ plane for 2HDM+a signals with sin$\theta$ = 0.35, $m_{\chi}$ = 10 GeV and $m_a$ = 250 GeV.</a> </ul> <b>Truth Code snippets</b> are available under "Resources" (purple button on the left)
The observed exclusion contour at 95% CL as a function of the $m_a$ vs. $m_{H^{\pm}}$ and assuming tan$\beta$ = 1, $m_{\mathrm{DM}} = 10 \mathrm{GeV}$, $g_{\chi} = 1$ and sin$\theta = 0.7$. Masses that are within the contours are excluded. Only signals simulating the tW+DM final states are considered in this contour.
The expected exclusion contour at 95% CL as a function of the $m_a$ vs. $m_{H^{\pm}}$ and assuming tan$\beta$ = 1, $m_{\mathrm{DM}} = 10 \mathrm{GeV}$, $g_{\chi} = 1$ and sin$\theta = 0.7$. Masses that are within the contours are excluded. Only signals simulating the tW+DM final states are considered in this contour.
This Letter presents the measurement of the fiducial and differential cross-sections of the electroweak production of a $Z \gamma$ pair in association with two jets. The analysis uses 140 fb$^{-1}$ of LHC proton-proton collision data taken at $\sqrt{s}$=13 TeV recorded by the ATLAS detector during the years 2015-2018. Events with a $Z$ boson candidate decaying into either an $e^+e^-$ or $\mu^+ \mu^-$ pair, a photon and two jets are selected. The electroweak component is extracted by requiring a large dijet invariant mass and a large rapidity gap between the two jets and is measured with an observed and expected significance well above five standard deviations. The fiducial $pp \rightarrow Z \gamma jj$ cross-section for the electroweak production is measured to be 3.6 $\pm$ 0.5 fb. The total fiducial cross-section that also includes contributions where the jets arise from strong interactions is measured to be $16.8^{+2.0}_{-1.8}$ fb. The results are consistent with the Standard Model predictions. Differential cross-sections are also measured using the same events and are compared with parton-shower Monte Carlo simulations. Good agreement is observed between data and predictions.
Post-fit mjj distributions in the mjj>500 GeV SR. The uncertainty band around the expectation includes all systematic uncertainties (including MC statistical uncertainty) and takes into account their correlations as obtained from the fit. The error bar around the data points represents the data statistical uncertainty. Events beyond the upper limit of the histogram are included in the last bin.
Post-fit mjj distributions in the mjj>500 GeV CR. The uncertainty band around the expectation includes all systematic uncertainties (including MC statistical uncertainty) and takes into account their correlations as obtained from the fit. The error bar around the data points represents the data statistical uncertainty. Events beyond the upper limit of the histogram are included in the last bin.
Post-fit mjj distributions in the mjj>150 GeV Extended SR. The uncertainty band around the expectation includes all systematic uncertainties (including MC statistical uncertainty) and takes into account their correlations as obtained from the fit. The error bar around the data points represents the data statistical uncertainty. Events beyond the upper limit of the histogram are included in the last bin.
A search for a long-lived, heavy neutral lepton ($\mathcal{N}$) in 139 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The $\mathcal{N}$ is produced via $W \rightarrow \mathcal{N} \mu$ or $W \rightarrow \mathcal{N} e$ and decays into two charged leptons and a neutrino, forming a displaced vertex. The $\mathcal{N}$ mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the $\mathcal{N}$ with the left-handed neutrino states for the $\mathcal{N}$ mass range $3$ GeV $< m_{\mathcal{N}} < 15$ GeV. For the first time, limits are given for both single-flavor and multiflavor mixing scenarios motivated by neutrino flavor oscillation results for both the normal and inverted neutrino-mass hierarchies.
Expected and observed 95% CL for the 1SFH e Dirac model.
Expected and observed 95% CL for the 1SFH e Majorana model.
Expected and observed 95% CL for the 1SFH mu Dirac model.
Cross-section measurements for a $Z$ boson produced in association with high-transverse-momentum jets ($p_{\mathrm{T}} \geq 100$ GeV) and decaying into a charged-lepton pair ($e^+e^-,\mu^+\mu^-$) are presented. The measurements are performed using proton-proton collisions at $\sqrt{s}=13$ TeV corresponding to an integrated luminosity of $139$ fb$^{-1}$ collected by the ATLAS experiment at the LHC. Measurements of angular correlations between the $Z$ boson and the closest jet are performed in events with at least one jet with $p_{\mathrm{T}} \geq 500$ GeV. Event topologies of particular interest are the collinear emission of a $Z$ boson in dijet events and a boosted $Z$ boson recoiling against a jet. Fiducial cross sections are compared with state-of-the-art theoretical predictions. The data are found to agree with next-to-next-to-leading-order predictions by NNLOjet and with the next-to-leading-order multi-leg generators MadGraph5_aMC@NLO and Sherpa.
Measured fiducial differential cross sections for the Z boson p$_{\mathrm{T}}$ in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
Measured fiducial differential cross sections for the leading jet p$_{\mathrm{T}}$ in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
Measured fiducial differential cross sections for the jet multiplicity in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
This paper presents a measurement of fiducial and differential cross-sections for $W^{+}W^{-}$ production in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS experiment at the Large Hadron Collider using a dataset corresponding to an integrated luminosity of 139 fb$^{-1}$. Events with exactly one electron, one muon and no hadronic jets are studied. The fiducial region in which the measurements are performed is inspired by searches for the electroweak production of supersymmetric charginos decaying to two-lepton final states. The selected events have moderate values of missing transverse momentum and the `stransverse mass' variable $m_{\textrm{T2}}$, which is widely used in searches for supersymmetry at the LHC. The ranges of these variables are chosen so that the acceptance is enhanced for direct $W^{+}W^{-}$ production and suppressed for production via top quarks, which is treated as a background. The fiducial cross-section and particle-level differential cross-sections for six variables are measured and compared with two theoretical SM predictions from perturbative QCD calculations.
Signal region detector-level distribution for the observable $|y_{e\mu}|$.
Signal region detector-level distribution for the observable $|\Delta \phi(e \mu)|$.
Signal region detector-level distribution for the observable $ \cos\theta^{\ast}$.
Cross-sections for the production of a $Z$ boson in association with two photons are measured in proton$-$proton collisions at a centre-of-mass energy of 13 TeV. The data used correspond to an integrated luminosity of 139 fb$^{-1}$ recorded by the ATLAS experiment during Run 2 of the LHC. The measurements use the electron and muon decay channels of the $Z$ boson, and a fiducial phase-space region where the photons are not radiated from the leptons. The integrated $Z(\rightarrow\ell\ell)\gamma\gamma$ cross-section is measured with a precision of 12% and differential cross-sections are measured as a function of six kinematic variables of the $Z\gamma\gamma$ system. The data are compared with predictions from MC event generators which are accurate to up to next-to-leading order in QCD. The cross-section measurements are used to set limits on the coupling strengths of dimension-8 operators in the framework of an effective field theory.
Measured fiducial-level integrated cross-section. NLO predictions from Sherpa 2.2.10 and MadGraph5_aMC@NLO 2.7.3 are also shown. The uncertainty in the predictions is divided into statistical and theoretical uncertainties (scale and PDF+$\alpha_{s}$).
Measured unfolded differential cross-section as a function of the leading photon transverse energy $E^{\gamma1}_{\mathrm{T}}$. NLO predictions from Sherpa 2.2.10 and MadGraph5_aMC@NLO 2.7.3 are also shown. The uncertainty in the predictions is divided into statistical and theoretical uncertainties (scale and PDF+$\alpha_{s}$).
Measured unfolded differential cross-section as a function of the subleading photon transverse energy $E^{\gamma2}_{\mathrm{T}}$. NLO predictions from Sherpa 2.2.10 and MadGraph5_aMC@NLO 2.7.3 are also shown. The uncertainty in the predictions is divided into statistical and theoretical uncertainties (scale and PDF+$\alpha_{s}$).
A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle $X$ decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to $qX$, with $X \rightarrow b\bar{b}$, and the other top quark decays according to the Standard Model, with the $W$ boson decaying leptonically. The final state is thus characterised by an isolated electron or muon and at least four jets. Events are categorised according to the multiplicity of jets and jets tagged as originating from $b$-quarks, and a neural network is used to discriminate between signal and background processes. The data analysed correspond to 139 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded with the ATLAS detector at the LHC. The 95% confidence-level upper limits between 0.019% and 0.062% are derived for the branching fraction $\mathcal{B}$($t \rightarrow uX$) and between 0.018% and 0.078% for the branching fraction $\mathcal{B}$($t \rightarrow cX$), for masses of the scalar particle $X$ between 20 and 160 GeV.
Expected and observed 95% CL upper limits for $\mathcal{B}$($t \rightarrow uX$) $\times$ $\mathcal{B}$($X \rightarrow b\bar{b}$). The bands surrounding the expected limits show the 68% and 95% confidence intervals, respectively.
Expected and observed 95% CL upper limits for $\mathcal{B}$($t \rightarrow cX$) $\times$ $\mathcal{B}$($X \rightarrow b\bar{b}$). The bands surrounding the expected limits show the 68% and 95% confidence intervals, respectively.
Expected and observed 95% CL upper limits for $\mathcal{B}$($t \rightarrow uH$) $\times$ $\mathcal{B}$($X \rightarrow b\bar{b}$) and $\mathcal{B}$($t \rightarrow cH$) $\times$ $\mathcal{B}$($X \rightarrow b\bar{b}$).
A search for a $WZ$ resonance, in the fully leptonic final state (electrons and muons), is performed using 139 fb$^{-1}$ of data collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The results are interpreted in terms of a singly charged Higgs boson of the Georgi$-$Machacek model, produced by $WZ$ fusion, and of a Heavy Vector Triplet, with the resonance produced by $WZ$ fusion or the Drell$-$Yan process. No significant excess over the Standard Model predictions is observed and limits are set on the production cross-section times branching ratio as a function of the resonance mass for these processes.
Comparisons of the data and the expected background distributions of the WZ invariant mass in the Drell-Yan signal region. The background predictions are obtained through a background-only simultaneous fit to the Drell-Yan signal region and the WZ-QCD Drell-Yan and ZZ Drell-Yan control regions. The yields are normalized to the bin width.
Comparisons of the data and the expected background distributions of the WZ invariant mass in the Drell-Yan signal region. The background predictions are obtained through a background-only simultaneous fit to the Drell-Yan signal region and the WZ-QCD Drell-Yan and ZZ Drell-Yan control regions. The yields are normalized to the bin width.
Comparisons of the data and the expected background distributions of the WZ invariant mass in the ANN-based VBF signal region. The background predictions are obtained through a background-only simultaneous fit to the VBF signal region and the WZ-QCD and ZZ VBF control regions. The yields are normalized to the bin width
A generic search for resonances is performed with events containing a $Z$ boson with transverse momentum greater than 100 GeV, decaying into $e^+e^-$ or $\mu^+\mu^-$. The analysed data collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider correspond to an integrated luminosity of 139 fb$^{-1}$. Two invariant mass distributions are examined for a localised excess relative to the expected Standard Model background in six independent event categories (and their inclusive sum) to increase the sensitivity. No significant excess is observed. Exclusion limits at 95% confidence level are derived for two cases: a model-independent interpretation of Gaussian-shaped resonances with the mass width between 3% and 10% of the resonance mass, and a specific heavy vector triplet model with the decay mode $W'\to ZW \to \ell\ell qq$.
Results of applying the BH algorithm to the mass spectra in the leading small-R jet category, using the fitted background estimations from the initial step
Results of applying the BH algorithm to the mass spectra in the leading bjet category, using the fitted background estimations from the initial step
Results of applying the BH algorithm to the mass spectra in the leading large-R jet category, using the fitted background estimations from the initial step
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