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.
The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon-nucleon center-of-mass energy $\sqrt{s_{_\mathrm{NN}}}=5.02~\mathrm{TeV}$ in comparison with $pp$ collisions at $\sqrt{s}=5.02~\mathrm{TeV}$. The Pb+Pb data, collected in 2018, have an integrated luminosity of $1.72~\mathrm{nb^{-1}}$, while the $pp$ data, collected in 2017, have an integrated luminosity of $260~\mathrm{pb}^{-1}$. Jets used in this analysis are clustered using the anti-$k_{t}$ algorithm with a radius parameter $R=0.4$. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale $r_\mathrm{g}$ of the first hard splitting inside the jet by reclustering them using the Cambridge-Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, $R_\mathrm{AA}$, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in $r_\mathrm{g}$, jet transverse momentum, and in intervals of collision centrality. The $R_\mathrm{AA}$ value is observed to depend significantly on jet $r_\mathrm{g}$. Jets produced with the largest measured $r_\mathrm{g}$ are found to be twice as suppressed as those with the smallest $r_\mathrm{g}$ in central Pb+Pb collisions. The $R_\mathrm{AA}$ values do not exhibit a strong variation with jet $p_\mathrm{T}$ in any of the $r_\mathrm{g}$ intervals. The $r_\mathrm{g}$ and $p_\mathrm{T}$ dependence of jet $R_\mathrm{AA}$ is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach.
Summary of jet double differential cross section in pp collisions at 5.02 TeV as a function of pT in bins of rg. Uncertainties are statistical and systematic, respectively.
Summary of jet double differential cross section in pp collisions at 5.02 TeV as a function of rg in bins of pT. Uncertainties are statistical and systematic, respectively.
Summary of per-event jet yields in Pb+Pb collisions at 5.02 TeV as a function of pT in bins of rg for 50-80% centrality interval, normalized by the respective centrality interval's <TAA>. Uncertainties are statistical and systematic, respectively.
Measurements of joint-polarisation states of $W$ and $Z$ gauge bosons in $W^{\pm}Z$ production are presented. The data set used corresponds to an integrated luminosity of $139$ fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $13$ TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The $W^{\pm}Z$ candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The simultaneous pair-production of longitudinally polarised vector bosons is measured for the first time with a significance of $7.1$ standard deviations. The measured joint helicity fractions integrated over the fiducial region are $f_{\mathrm{00}} = 0.067 \pm 0.010$, $f_{\mathrm{0T}} = 0.110 \pm 0.029$, $f_{\mathrm{T0}} = 0.179 \pm 0.023$ and $f_{\mathrm{TT}} = 0.644 \pm 0.032$, in agreement with the next-to-leading-order Standard Model predictions. Individual helicity fractions of the $W$ and $Z$ bosons are also measured and found to be consistent with joint helicity fractions within the expected amount of correlations. Both the joint and individual helicity fractions are also measured separately in $W^+Z$ and $W^-Z$ events. Inclusive and differential cross sections for several kinematic observables sensitive to polarisation are presented.
Measured fiducial Born-level cross section for a single leptonic decay channel $\ell'^\pm \nu \ell^+ \ell'^-$ of the $W$ and $Z$ bosons, where $\ell, \ell' = e, \mu$. The relative uncertainties are reported as percentages. The systematic uncertainties are in order of appearance: total uncorrelated systematic and correlated systematics related respectively to unfolding, electrons, muons, jets, reducible and irreducible backgrounds and pileup. The last bin is a cross section for all events above the lower end of the bin.
Correlation matrix for the unfolded cross section.
Measured fiducial Born-level cross section for a single leptonic decay channel $\ell'^\pm \nu \ell^+ \ell'^-$ of the $W$ and $Z$ bosons, where $\ell, \ell' = e, \mu$. The relative uncertainties are reported as percentages. The systematic uncertainties are in order of appearance: total uncorrelated systematic and correlated systematics related respectively to unfolding, electrons, muons, jets, reducible and irreducible backgrounds and pileup. The last bin is a cross section for all events above the lower end of the bin.
Constraints on the Higgs boson self-coupling are set by combining double-Higgs boson analyses in the $b\bar{b}b\bar{b}$, $b\bar{b}\tau^+\tau^-$ and $b\bar{b} \gamma \gamma$ decay channels with single-Higgs boson analyses targeting the $\gamma \gamma$, $ZZ^*$, $WW^*$, $\tau^+ \tau^-$ and $b\bar{b}$ decay channels. The data used in these analyses were recorded by the ATLAS detector at the LHC in proton$-$proton collisions at $\sqrt{s}=13$ TeV and correspond to an integrated luminosity of 126$-$139 fb$^{-1}$. The combination of the double-Higgs analyses sets an upper limit of $\mu_{HH} < 2.4$ at 95% confidence level on the double-Higgs production cross-section normalised to its Standard Model prediction. Combining the single-Higgs and double-Higgs analyses, with the assumption that new physics affects only the Higgs boson self-coupling ($\lambda_{HHH}$), values outside the interval $-0.4< \kappa_{\lambda}=(\lambda_{HHH}/\lambda_{HHH}^{\textrm{SM}})< 6.3$ are excluded at 95% confidence level. The combined single-Higgs and double-Higgs analyses provide results with fewer assumptions, by adding in the fit more coupling modifiers introduced to account for the Higgs boson interactions with the other Standard Model particles. In this relaxed scenario, the constraint becomes $-1.4 < \kappa_{\lambda} < 6.1$ at 95% CL.
Observed and expected 95% CL upper limits on the signal strength for double-Higgs production from the bbbb, bb$\tau\tau$ and bb$\gamma\gamma$ decay channels, and their statistical combination. The value $m_H$ = 125.09 GeV is assumed when deriving the predicted SM cross-section. The expected limit and the corresponding error bands are derived assuming the absence of the HH process and with all nuisance parameters profiled to the observed data.
Observed and expected 95% CL exclusion limits on the production cross-sections of the combined ggF HH and VBF HH processes as a function of $\kappa_\lambda$, for the three double-Higgs search channels and their combination. The expected limits assume no HH production. The red line shows the theory prediction for the combined ggF HH and VBF HH cross-section as a function of $\kappa_\lambda$ where all parameters and couplings are set to their SM values except for $\kappa_\lambda$. The band surrounding the red cross-section lines indicate the theoretical uncertainty of the predicted cross-section.
Observed and expected 95% CL exclusion limits on the production cross-sections of the VBF HH process as a function of $\kappa_{2V}$, for the three double-Higgs search channels and their combination. The expected limits assume no VBF HH production. The red line shows the predicted VBF HH cross-section as a function of $\kappa_{2V}$. The bands surrounding the red cross-section lines indicate the theoretical uncertainty of the predicted cross-section. The uncertainty band is smaller than the width of the plotted line.
A search for the pair-production of vector-like quarks optimized for decays into a $Z$ boson and a third-generation Standard Model quark is presented, using the full Run 2 dataset corresponding to 139 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV, collected in 2015-2018 with the ATLAS detector at the Large Hadron Collider. The targeted final state is characterized by the presence of a $Z$ boson with high transverse momentum, reconstructed from a pair of same-flavour leptons with opposite-sign charges, as well as by the presence of $b$-tagged jets and high-transverse-momentum large-radius jets reconstructed from calibrated smaller-radius jets. Events with exactly two or at least three leptons are used, which are further categorized by the presence of boosted $W$, $Z$, and Higgs bosons and top quarks. The categorization is performed using a neural-network-based boosted object tagger to enhance the sensitivity to signal relative to the background. No significant excess above the background expectation is observed and exclusion limits at 95% confidence level are set on the masses of the vector-like partners $T$ and $B$ of the top and bottom quarks, respectively. In the singlet model, the limits allow $m_T > 1.27$ TeV and $m_B > 1.20$ TeV. In the doublet model, allowed masses are $m_T > 1.46$ TeV and $m_B >1.32$ TeV. In the case of 100% branching ratio for $T\rightarrow Zt$ and 100% branching ratio for $B\rightarrow Zb$, the limits allow $m_T > 1.60$ TeV and $m_B > 1.42$ TeV, respectively.
Expected and observed lower limits on B masses at 95% CL in the BR plane from the combination of the two analysis channels for all BR configurations when assuming a total BR of 100% for H, W and Z.
Expected and observed lower limits on T masses at 95% CL in the BR plane from the combination of the two analysis channels for all BR configurations when assuming a total BR of 100% for H, W and Z.
Expected and observed combined limits at 95% CL on the production cross-section of vector-like T for 100% $T\rightarrow Zt$.
This paper reports a search for Higgs boson pair ($hh$) production in association with a vector boson ($W$ or $Z$) using 139 $fb^{-1}$ of proton-proton collision data at $\sqrt{s}=$ 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The search is performed in final states in which the vector boson decays leptonically ($W\to\ell\nu, Z\to\ell\ell,\nu\nu$ with $\ell=e, \mu$) and the Higgs bosons each decay into a pair of $b$-quarks. It targets $Vhh$ signals from both non-resonant $hh$ production, present in the Standard Model (SM), and resonant $hh$ production, as predicted in some SM extensions. A 95% confidence-level upper limit of 183 (87) times the SM cross-section is observed (expected) for non-resonant $Vhh$ production when assuming the kinematics are as expected in the SM. Constraints are also placed on Higgs boson coupling modifiers. For the resonant search, upper limits on the production cross-sections are derived for two specific models: one is the production of a vector boson along with a neutral heavy scalar resonance $H$, in the mass range 260-1000 GeV, that decays into $hh$, and the other is the production of a heavier neutral pseudoscalar resonance $A$ that decays into a $Z$ boson and $H$ boson, where the $A$ boson mass is 360-800 GeV and the $H$ boson mass is 260-400 GeV. Constraints are also derived in the parameter space of two-Higgs-doublet models.
Acceptance times efficiency as a function of resonant mass for each event selection step in the search for a neutral heavy scalar resonance produced in association with a Z boson decaying to neutrinos.
Acceptance times efficiency as a function of resonant mass for each event selection step in the search for a neutral heavy scalar resonance produced in association with a W boson decaying to a charged lepton and a neutrino.
Acceptance times efficiency as a function of resonant mass for each event selection step in the search for a neutral heavy scalar resonance produced in association with a Z boson decaying to charged leptons.
Inclusive and differential measurements of the top-antitop ($t\bar{t}$) charge asymmetry $A_\text{C}^{t\bar{t}}$ and the leptonic asymmetry $A_\text{C}^{\ell\bar{\ell}}$ are presented in proton-proton collisions at $\sqrt{s} = 13$ TeV recorded by the ATLAS experiment at the CERN Large Hadron Collider. The measurement uses the complete Run 2 dataset, corresponding to an integrated luminosity of 139 fb$^{-1}$, combines data in the single-lepton and dilepton channels, and employs reconstruction techniques adapted to both the resolved and boosted topologies. A Bayesian unfolding procedure is performed to correct for detector resolution and acceptance effects. The combined inclusive $t\bar{t}$ charge asymmetry is measured to be $A_\text{C}^{t\bar{t}} = 0.0068 \pm 0.0015$, which differs from zero by 4.7 standard deviations. Differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the $t\bar{t}$ system. Both the inclusive and differential measurements are found to be compatible with the Standard Model predictions, at next-to-next-to-leading order in quantum chromodynamics perturbation theory with next-to-leading-order electroweak corrections. The measurements are interpreted in the framework of the Standard Model effective field theory, placing competitive bounds on several Wilson coefficients.
- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Results:</b> <ul> <li><a href="132116?version=2&table=Resultsforchargeasymmetryinclusive">$A_C^{t\bar{t}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvsmtt">$A_C^{t\bar{t}}$ vs $m_{t\bar{t}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvspttt">$A_C^{t\bar{t}}$ vs $p_{T,t\bar{t}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvsbetatt">$A_C^{t\bar{t}}$ vs $\beta_{z,t\bar{t}}$</a> <li><a href="132116?version=2&table=Resultsforleptonicchargeasymmetryinclusive">$A_C^{\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvsllmll">$A_C^{\ell\bar{\ell}}$ vs $m_{\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvsllptll">$A_C^{\ell\bar{\ell}}$ vs $p_{T,\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=Resultsforchargeasymmetryvsllbetall">$A_C^{\ell\bar{\ell}}$ vs $\beta_{z,\ell\bar{\ell}}$</a> </ul> <b>Bounds on the Wilson coefficients:</b> <ul> <li><a href="132116?version=2&table=BoundsonWilsoncoefficientschargeasymmetryinclusive">$A_C^{t\bar{t}}$</a> <li><a href="132116?version=2&table=BoundsonWilsoncoefficientschargeasymmetryvsmtt">$A_C^{t\bar{t}}$ vs $m_{t\bar{t}}$</a> </ul> <b>Ranking of systematic uncertainties:</b></br> Inclusive:<a href="132116?version=2&table=NPrankingchargeasymmetryinclusive">$A_C^{t\bar{t}}$</a></br> <b>$A_C^{t\bar{t}}$ vs $\beta_{z,t\bar{t}}$:</b> <ul> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsbetattbin0">$\beta_{z,t\bar{t}} \in[0,0.3]$</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsbetattbin1">$\beta_{z,t\bar{t}} \in[0.3,0.6]$</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsbetattbin2">$\beta_{z,t\bar{t}} \in[0.6,0.8]$</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsbetattbin3">$\beta_{z,t\bar{t}} \in[0.8,1]$</a> </ul> <b>$A_C^{t\bar{t}}$ vs $m_{t\bar{t}}$:</b> <ul> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsmttbin0">$m_{t\bar{t}}$ < $500$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsmttbin1">$m_{t\bar{t}} \in [500,750]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsmttbin2">$m_{t\bar{t}} \in [750,1000]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsmttbin3">$m_{t\bar{t}} \in [1000,1500]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsmttbin4">$m_{t\bar{t}}$ > $1500$GeV</a> </ul> <b>$A_C^{t\bar{t}}$ vs $p_{T,t\bar{t}}$:</b> <ul> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsptttbin0">$p_{T,t\bar{t}} \in [0,30]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsptttbin1">$p_{T,t\bar{t}} \in[30,120]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsptttbin2">$p_{T,t\bar{t}}$ > $120$GeV</a> </ul> Inclusive leptonic:<a href="132116?version=2&table=NPrankingleptonicchargeasymmetryinclusive">$A_C^{\ell\bar{\ell}}$</a></br> <b>$A_C^{\ell\bar{\ell}}$ vs $\beta_{z,\ell\bar{\ell}}$</b> <ul> <li><a href="132116?version=2&tableNPrankingchargeasymmetry=vsllbetallbin0">$\beta_{z,\ell\bar{\ell}} \in [0,0.3]$</a> <li><a href="132116?version=2&tableNPrankingchargeasymmetry=vsllbetallbin1">$\beta_{z,\ell\bar{\ell}} \in [0.3,0.6]$</a> <li><a href="132116?version=2&tableNPrankingchargeasymmetry=vsllbetallbin2">$\beta_{z,\ell\bar{\ell}} \in [0.6,0.8]$</a> <li><a href="132116?version=2&tableNPrankingchargeasymmetry=vsllbetallbin3">$\beta_{z,\ell\bar{\ell}} \in [0.8,1]$</a> </ul> <b>$A_C^{\ell\bar{\ell}}$ vs $m_{\ell\bar{\ell}}$</b> <ul> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllmllbin0">$m_{\ell\bar{\ell}}$ < $200$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllmllbin1">$m_{\ell\bar{\ell}} \in [200,300]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllmllbin2">$m_{\ell\bar{\ell}} \in [300,400]$Ge$</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllmllbin3">$m_{\ell\bar{\ell}}$ > $400$GeV</a> </ul> <b>$A_C^{\ell\bar{\ell}}$ vs $p_{T,\ell\bar{\ell}}$</b> <ul> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllptllbin0">$p_{T,\ell\bar{\ell}}\in [0,20]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllptllbin1">$p_{T,\ell\bar{\ell}}\in[20,70]$GeV</a> <li><a href="132116?version=2&table=NPrankingchargeasymmetryvsllptllbin2">$p_{T,\ell\bar{\ell}}$ > $70$GeV</a> </ul> <b>NP correlations:</b> <ul> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryinclusive">$A_C^{t\bar{t}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvsmtt">$A_C^{t\bar{t}}$ vs $m_{t\bar{t}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvspttt">$A_C^{t\bar{t}}$ vs $p_{T,t\bar{t}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvsbetatt">$A_C^{t\bar{t}}$ vs $\beta_{z,t\bar{t}}$</a> <li><a href="132116?version=2&table=NPcorrelationsleptonicchargeasymmetryinclusive">$A_c^{\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvsllmll">$A_c^{\ell\bar{\ell}}$ vs $m_{\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvsllptll">$A_C^{\ell\bar{\ell}}$ vs $p_{T,\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=NPcorrelationschargeasymmetryvsllbetall">$A_C^{\ell\bar{\ell}}$ vs $\beta_{z,\ell\bar{\ell}}$</a> </ul> <b>Covariance matrices:</b> <ul> <li><a href="132116?version=2&table=Covariancematrixchargeasymmetryvsmtt">$A_C^{t\bar{t}}$ vs $m_{t\bar{t}}$</a> <li><a href="132116?version=2&table=Covariancematrixchargeasymmetryvspttt">$A_C^{t\bar{t}}$ vs $p_{T,t\bar{t}}$</a> <li><a href="132116?version=2&table=Covariancematrixchargeasymmetryvsbetatt">$A_C^{t\bar{t}}$ vs $\beta_{z,t\bar{t}}$</a> <li><a href="132116?version=2&table=Covariancematrixleptonicchargeasymmetryvsllmll">$A_c^{\ell\bar{\ell}}$ vs $m_{\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=Covariancematrixleptonicchargeasymmetryvsllptll">$A_C^{\ell\bar{\ell}}$ vs $p_{T,\ell\bar{\ell}}$</a> <li><a href="132116?version=2&table=Covariancematrixleptonicchargeasymmetryvsllbetall">$A_C^{\ell\bar{\ell}}$ vs $\beta_{z,\ell\bar{\ell}}$</a> </ul>
The unfolded inclusive charge asymmetry. The measured values are given with statistical and systematic uncertainties. The SM theory predictions calculated at NNLO in QCD and NLO in EW theory are listed, and the impact of the linear term of the Wilson coefficient on the $A_C^{t\bar{t}}$ prediction is shown for two different values. The scale uncertainty is obtained by varying renormalisation and factorisation scales independently by a factor of 2 or 0.5 around $\mu_0$ to calculate the maximum and minimum value of the asymmetry, respectively. The nominal value $\mu_0$ is chosen as $H_T/4$. The variations in which one scale is multiplied by 2 while the other scale is divided by 2 are excluded. Finally, the scale and MC integration uncertainties are added in quadrature.
The unfolded differential charge asymmetry as a function of the invariant mass of the top pair system. The measured values are given with statistical and systematic uncertainties. The SM theory predictions calculated at NNLO in QCD and NLO in EW theory are listed, and the impact of the linear term of the Wilson coefficient on the $A_C^{t\bar{t}}$ prediction is shown for two different values. The scale uncertainty is obtained by varying renormalisation and factorisation scales independently by a factor of 2 or 0.5 around $\mu_0$ to calculate the maximum and minimum value of the asymmetry, respectively. The nominal value $\mu_0$ is chosen as $H_T/4$. The variations in which one scale is multiplied by 2 while the other scale is divided by 2 are excluded. Finally, the scale and MC integration uncertainties are added in quadrature.
The Standard Model of particle physics describes the known fundamental particles and forces that make up our universe, with the exception of gravity. One of the central features of the Standard Model is a field that permeates all of space and interacts with fundamental particles. The quantum excitation of this field, known as Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the Standard Model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, allowing much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and $W$ and $Z$ bosons -- the carriers of the strong, electromagnetic, and weak forces -- are studied in detail. Interactions with three third-generation matter particles (bottom ($b$) and top ($t$) quarks, and tau leptons ($\tau$)) are well measured and indications of interactions with a second-generation particle (muons, $\mu$) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the Standard Model.
Observed and predicted cross sections for different Higgs boson production processes, measured assuming SM values for the decay branching fractions. The lower panels show the ratios of the measured values to their SM predictions. The $p$-value for compatibility of the measurement and the SM prediction is 65%.
Observed and predicted branching fractions for different Higgs boson decay modes measured assuming SM values for the production cross sections. The lower panels show the ratios of the measured values to their SM predictions. The $p$-value for compatibility of the measurement and the SM prediction is 56%.
Ratio of observed rate to predicted SM event rate for different combinations of Higgs boson production and decay processes. The narrow grey bands indicate the theory uncertainties in the SM cross-section times the branching fraction predictions. The $p$-value for compatibility of the measurement and the SM prediction is 72%.
Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including $pp$ and $p$+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36 nb$^{-1}$ of $p$+Pb and 3.6 pb$^{-1}$ of $pp$ collisions at 5.02 TeV. The yields of charged hadrons with $p_\mathrm{T}^\mathrm{ch} >0.5$ GeV near and opposite in azimuth to jets with $p_\mathrm{T}^\mathrm{jet} > 30$ or $60$ GeV, and the ratios of these yields between $p$+Pb and $pp$ collisions, $I_{p\mathrm{Pb}}$, are reported. The collision centrality of $p$+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The $I_{p\mathrm{Pb}}$ values are consistent with unity within a few percent for hadrons with $p_\mathrm{T}^\mathrm{ch} >4$ GeV at all centralities. These data provide new, strong constraints which preclude almost any parton energy loss in central $p$+Pb collisions.
The per-jet charged particle yield in pPb and pp collisions for hadrons near a $p_{T}^{\textrm{jet}} > 30~\textrm{GeV}$ jet ($\Delta\phi_{\textrm{ch,jet}} < \pi/8$).
The per-jet charged particle yield in pPb and pp collisions for hadrons opposite to a $p_{T}^{\textrm{jet}} > 30~\textrm{GeV}$ jet ($\Delta\phi_{\textrm{ch,jet}} > 7\pi/8$).
The per-jet charged particle yield in pPb and pp collisions for hadrons near a $p_{T}^{\textrm{jet}} > 60~\textrm{GeV}$ jet ($\Delta\phi_{\textrm{ch,jet}} < \pi/8$).
A combination of measurements of the inclusive top-quark pair production cross-section performed by ATLAS and CMS in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV at the LHC is presented. The cross-sections are obtained using top-quark pair decays with an opposite-charge electron-muon pair in the final state and with data corresponding to an integrated luminosity of about 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and about 20 fb$^{-1}$ at $\sqrt{s}=8$ TeV for each experiment. The combined cross-sections are determined to be $178.5 \pm 4.7$ pb at $\sqrt{s}=7$ TeV and $243.3^{+6.0}_{-5.9}$ pb at $\sqrt{s}=8$ TeV with a correlation of 0.41, using a reference top-quark mass value of 172.5 GeV. The ratio of the combined cross-sections is determined to be $R_{8/7}= 1.363\pm 0.032$. The combined measured cross-sections and their ratio agree well with theory calculations using several parton distribution function (PDF) sets. The values of the top-quark pole mass (with the strong coupling fixed at 0.118) and the strong coupling (with the top-quark pole mass fixed at 172.5 GeV) are extracted from the combined results by fitting a next-to-next-to-leading-order plus next-to-next-to-leading-log QCD prediction to the measurements. Using a version of the NNPDF3.1 PDF set containing no top-quark measurements, the results obtained are $m_t^\text{pole} = 173.4^{+1.8}_{-2.0}$ GeV and $\alpha_\text{s}(m_Z)= 0.1170^{+ 0.0021}_{-0.0018}$.
Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.
Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.