Search for exotic decays of the Higgs boson into $b\bar{b}$ and missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
CERN-EP-2021-098, 2021.
Inspire Record 1917172 DOI 10.17182/hepdata.104855

A search for the exotic decay of the Higgs boson ($H$) into a $b\bar{b}$ resonance plus missing transverse momentum is described. The search is performed with the ATLAS detector at the Large Hadron Collider using 139 $\mathrm{fb}^{-1}$ of $pp$ collisions at $\sqrt{s} = 13$ TeV. The search targets events from $ZH$ production in an NMSSM scenario where $H \rightarrow \tilde{\chi}^{0}_{2}\tilde{\chi}^{0}_{1}$, with $\tilde{\chi}^{0}_{2} \rightarrow {a} \tilde{\chi}^{0}_{1}$, where $a$ is a light pseudoscalar Higgs boson and $\tilde{\chi}^{0}_{1,2}$ are the two lightest neutralinos. The decay of the $a$ boson into a pair of $b$-quarks results in a peak in the dijet invariant mass distribution. The final-state signature consists of two leptons, two or more jets, at least one of which is identified as originating from a $b$-quark, and missing transverse momentum. Observations are consistent with Standard Model expectations and upper limits are set on the product of cross section times branching ratio for a three-dimensional scan of the masses of the $\tilde{\chi}^{0}_{2}$, $\tilde{\chi}^{0}_{1}$ and $a$ boson.

20 data tables

Distribution of the dijet invariant mass in CRZ. The Z+HF and $t\bar{t}$ scale factors, described in the text, have been applied to the simulated samples. The distribution labeled "Signal" is for the model with ($m_a$, $m_{\tilde{\chi}_{1}^{0}}$, $m_{\tilde{\chi}_{2}^{0}}$) = (45 GeV, 10 GeV, 80 GeV).

Distribution of the missing transverse energy in VRMET. The Z+HF and $t\bar{t}$ scale factors, described in the text, have been applied to the simulated samples. The distribution labeled "Signal" is for the model with ($m_a$, $m_{\tilde{\chi}_{1}^{0}}$, $m_{\tilde{\chi}_{2}^{0}}$) = (45 GeV, 10 GeV, 80 GeV).

Distribution of the dijet invariant mass in CRTop. The Z+HF and $t\bar{t}$ scale factors, described in the text, have been applied to the simulated samples. The distribution labeled "Signal" is for the model with ($m_a$, $m_{\tilde{\chi}_{1}^{0}}$, $m_{\tilde{\chi}_{2}^{0}}$) = (45 GeV, 10 GeV, 80 GeV).

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Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
2021.
Inspire Record 1915357 DOI 10.17182/hepdata.107760

This paper presents the measurement of the electroweak production of two jets in association with a $Z\gamma$ pair with the $Z$ boson decaying into two neutrinos. It also presents the search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. For electroweak production of $Z\gamma$ in association with two jets, the background-only hypothesis is rejected with an observed (expected) significance of 5.2 (5.1) standard deviations. The measured fiducial cross-section for this process is 1.31$\pm$0.29 fb. Observed (expected) upper limit of 0.37 (0.34) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson to a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017), assuming the 125 GeV Standard Model Higgs boson production cross-section.

16 data tables

Post-fit results for all $m_\text{jj}$ SR and CR bins in the EW $Z \gamma + \text{jets}$ cross-section measurement with the $\mu_{Z \gamma_\text{EW}}$ signal normalization floating. The post-fit uncertainties include statistical, experimental, and theory contributions.

Post-fit results for all DNN SR and CR bins in the search for $H \to \text{inv.}$ with the $\mathcal{B}_\text{inv}$ signal normalization set to zero. For the $Z_\text{Rev.Cen.}^\gamma$ CR, the third bin contains all events with DNN output score values of 0.6-1.0. The $H \to \text{inv.}$ signal is scaled to a $\mathcal{B}_\text{inv}$ of 37%. The post-fit uncertainties include statistical, experimental, and theoretical contributions.

Post-fit results for the ten [$m_\text{jj}$, $m_\text{T}$] bins constituting the SR and CRs defined for the dark photon search with the $\mathcal{B}(H \to \gamma \gamma_\text{d})$ signal normalization set to zero. A $H \to \gamma \gamma_\text{d}$ signal is shown for two different mass hypotheses (125 GeV, 500 GeV) and scaled to a branching ratio of 2% and 1%, respectively. The post-fit uncertainties include statistical, experimental, and theoretical contributions.

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Measurement of the nuclear modification factor for muons from charm and bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
CERN-EP-2021-153, 2021.
Inspire Record 1914582 DOI 10.17182/hepdata.111123

Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark-gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and $pp$ collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV with the ATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were collected in 2015 and 2018 with sampled integrated luminosities of $208~\mathrm{\mu b}^{-1}$ and $38~\mathrm{\mu b^{-1}}$, respectively, and $pp$ data with a sampled integrated luminosity of $1.17~\mathrm{pb}^{-1}$ were collected in 2017. Muons from heavy-flavour semileptonic decays are separated from the light-flavour hadronic background using the momentum imbalance between the inner detector and muon spectrometer measurements, and muons originating from charm and bottom decays are further separated via the muon track's transverse impact parameter. Differential yields in Pb+Pb collisions and differential cross sections in $pp$ collisions for such muons are measured as a function of muon transverse momentum from 4 GeV to 30 GeV in the absolute pseudorapidity interval $|\eta| < 2$. Nuclear modification factors for charm and bottom muons are presented as a function of muon transverse momentum in intervals of Pb+Pb collision centrality. The measured nuclear modification factors quantify a significant suppression of the yields of muons from decays of charm and bottom hadrons, with stronger effects for muons from charm hadron decays.

6 data tables

Summary of charm muon double differential cross section in pp collisions at 5.02 TeV as a function of pT. Uncertainties are statistical and systematic, respectively.

Summary of charm muon per-event invariant yields in Pb+Pb collisions at 5.02 TeV as a function of pT for five different centrality intervals. Uncertainties are statistical and systematic, respectively.

Summary of bottom muon per-event invariant yields in Pb+Pb collisions at 5.02 TeV as a function of pT for five different centrality intervals. Uncertainties are statistical and systematic, respectively.

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Search for charginos and neutralinos in final states with two boosted hadronically decaying bosons and missing transverse momentum in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
CERN-EP-2021-127, 2021.
Inspire Record 1906174 DOI 10.17182/hepdata.104458

A search for charginos and neutralinos at the Large Hadron Collider is reported using fully hadronic final states and missing transverse momentum. Pair-produced charginos or neutralinos are explored, each decaying into a high-$p_{\text{T}}$ Standard Model weak boson. Fully-hadronic final states are studied to exploit the advantage of the large branching ratio, and the efficient background rejection by identifying the high-$p_{\text{T}}$ bosons using large-radius jets and jet substructure information. An integrated luminosity of 139 fb$^{-1}$ of proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 13 TeV is used. No significant excess is found beyond the Standard Model expectation. The 95% confidence level exclusion limits are set on wino or higgsino production with varying assumptions in the decay branching ratios and the type of the lightest supersymmetric particle. A wino (higgsino) mass up to 1060 (900) GeV is excluded when the lightest SUSY particle mass is below 400 (240) GeV and the mass splitting is larger than 400 (450) GeV. The sensitivity to high-mass wino and higgsino is significantly extended compared with the previous LHC searches using the other final states.

145 data tables

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Cutflow:</b> <a href="104458?version=1&table=Cut flows for the representative signals">table</a><br/><br/> <b>Boson tagging:</b> <ul> <li><a href="104458?version=1&table=%24W%2FZ%5Crightarrow%20qq%24%20tagging%20efficiency">$W/Z\rightarrow qq$ tagging efficiency</a> <li><a href="104458?version=1&table=%24W%2FZ%5Crightarrow%20qq%24%20tagging%20rejection">$W/Z\rightarrow qq$ tagging rejection</a> <li><a href="104458?version=1&table=%24Z%2Fh%20%5Crightarrow%20bb%24%20tagging%20efficiency">$Z/h\rightarrow bb$ tagging efficiency</a> <li><a href="104458?version=1&table=%24Z%2Fh%20%5Crightarrow%20bb%24%20tagging%20rejection">$Z/h\rightarrow bb$ tagging rejection</a> <li><a href="104458?version=1&table=%24W%5Crightarrow%20qq%24%20tagging%20efficiency%20(vs%20official%20WP)">$W\rightarrow qq$ tagging efficiency (vs official WP)</a> <li><a href="104458?version=1&table=%24W%5Crightarrow%20qq%24%20tagging%20rejection%20(vs%20official%20WP)">$W\rightarrow qq$ tagging rejection (vs official WP)</a> <li><a href="104458?version=1&table=%24Z%5Crightarrow%20qq%24%20tagging%20efficiency%20(vs%20official%20WP)">$Z\rightarrow qq$ tagging efficiency (vs official WP)</a> <li><a href="104458?version=1&table=%24Z%5Crightarrow%20qq%24%20tagging%20rejection%20(vs%20official%20WP)">$Z\rightarrow qq$ tagging rejection (vs official WP)</a> </ul> <b>Systematic uncertainty:</b> <a href="104458?version=1&table=Total%20systematic%20uncertainties">table</a><br/><br/> <b>Summary of SR yields:</b> <a href="104458?version=1&table=Data%20yields%20and%20background%20expectation%20in%20the%20SRs">table</a><br/><br/> <b>Expected background yields and the breakdown:</b> <ul> <li><a href="104458?version=1&table=Data%20yields%20and%20background%20breakdown%20in%20SR">CR0L / SR</a> <li><a href="104458?version=1&table=Data%20yields%20and%20background%20breakdown%20in%20CR%2FVR%201L(1Y)">CR1L / VR1L /CR1Y / VR1Y</a> </ul> <b>SR distributions:</b> <ul> <li><a href="104458?version=1&table=Effective mass distribution in SR-4Q-VV">SR-4Q-VV: Effective mass</a> <li><a href="104458?version=1&table=Leading large-$R$ jet mass distribution in SR-4Q-VV">SR-4Q-VV: Leading jet mass</a> <li><a href="104458?version=1&table=Leading large-$R$ jet $D_{2}$ distribution in SR-4Q-VV">SR-4Q-VV: Leading jet $D_{2}$</a> <li><a href="104458?version=1&table=Sub-leading large-$R$ jet mass distribution in SR-4Q-VV">SR-4Q-VV: Sub-leading jet mass</a> <li><a href="104458?version=1&table=Sub-leading large-$R$ jet $D_{2}$ distribution in SR-4Q-VV">SR-4Q-VV: Sub-leading jet $D_{2}$</a> <li><a href="104458?version=1&table=$m_{T2}$ distribution in SR-2B2Q-VZ">SR-2B2Q-VZ: $m_{\textrm{T2}}$</a> <li><a href="104458?version=1&table=bb-tagged jet mass distribution in SR-2B2Q-VZ">SR-2B2Q-VZ: bb-tagged jet mass</a> <li><a href="104458?version=1&table=Effective mass distribution in SR-2B2Q-VZ">SR-2B2Q-VZ: Effective mass</a> <li><a href="104458?version=1&table=$m_{T2}$ distribution in SR-2B2Q-Vh">SR-2B2Q-Vh: $m_{\textrm{T2}}$</a> <li><a href="104458?version=1&table=bb-tagged jet mass distribution in SR-2B2Q-Vh">SR-2B2Q-Vh: bb-tagged jet mass</a> <li><a href="104458?version=1&table=Effective mass distribution in SR-2B2Q-Vh">SR-2B2Q-Vh: Effective mass</a> </ul> <b>Exclusion limit:</b> <ul> <li>$(\tilde{W},~\tilde{B})$-SIM model (C1C1-WW): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) simplified model (C1C1-WW)">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1C1-WW)">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li>Expected limit ($-1\sigma_{\textrm{exp}}$): (No mass point could be excluded) <li><a href="104458?version=1&table=Obs limit on (W~, B~) simplified model (C1C1-WW)">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1C1-WW)">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~, B~) simplified model (C1C1-WW)">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) simplified model (C1N2-WZ)">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1N2-WZ)">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(W~, B~) simplified model (C1N2-WZ)">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) simplified model (C1N2-WZ)">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1N2-WZ)">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~, B~) simplified model (C1N2-WZ)">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{B})$-SIM model (C1N2-Wh): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) simplified model (C1N2-Wh)">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1N2-Wh)">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(W~, B~) simplified model (C1N2-Wh)">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) simplified model (C1N2-Wh)">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~, B~) simplified model (C1N2-Wh)">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~, B~) simplified model (C1N2-Wh)">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=0\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) B(N2->ZN1) = 0%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) B(N2->ZN1) = 0%">Observed limit</a> </ul> <li>$(\tilde{W},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=25\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) B(N2->ZN1) = 25%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) B(N2->ZN1) = 25%">Observed limit</a> </ul> <li>$(\tilde{W},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=50\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) B(N2->ZN1) = 50%">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%25">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(W~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%25">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) B(N2->ZN1) = 50%">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%25">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=75\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) B(N2->ZN1) = 75%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) B(N2->ZN1) = 75%">Observed limit</a> </ul> <li>$(\tilde{W},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=100\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, B~) B(N2->ZN1) = 100%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (W~, B~) B(N2->ZN1) = 100%">Observed limit</a> </ul> <li>$(\tilde{H},~\tilde{B})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})=50\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (H~, B~) B(N2->ZN1) = 50%">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(H~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%25">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li>Expected limit ($-1\sigma_{\textrm{exp}}$): (No mass point could be excluded) <li><a href="104458?version=1&table=Obs limit on (H~, B~) B(N2->ZN1) = 50%">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(H~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(H~%2C%20B~)%20B(N2-%3EZN1)%20%3D%2050%25">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{H})$ model ($\textrm{tan}\beta=10,~\mu>0$): <ul> <li><a href="104458?version=1&table=Exp limit on (W~, H~), tanb = 10, mu>0">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (W~, H~), tanb = 10, mu>0">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{H},~\tilde{W})$ model ($\textrm{tan}\beta=10,~\mu>0$): <ul> <li><a href="104458?version=1&table=Exp limit on (H~, W~), tanb = 10, mu>0">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li>Expected limit ($-1\sigma_{\textrm{exp}}$): (No mass point could be excluded) <li><a href="104458?version=1&table=Obs limit on (H~, W~), tanb = 10, mu>0">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20mu%3E0">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{W},~\tilde{H})$ model ($\textrm{tan}\beta=10$) on ($\mu$,$M_{2}$) plane: <ul> <li><a href="104458?version=1&table=Exp limit on (W~, H~), tanb = 10, M2 vs mu">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (W~, H~), tanb = 10, M2 vs mu">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(W~%2C%20H~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{H},~\tilde{W})$ model ($\textrm{tan}\beta=10$) on ($\mu$,$M_{2}$) plane: <ul> <li><a href="104458?version=1&table=Exp limit on (H~, W~), tanb = 10, M2 vs mu">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li>Expected limit ($-1\sigma_{\textrm{exp}}$): (No mass point could be excluded) <li><a href="104458?version=1&table=Obs limit on (H~, W~), tanb = 10, M2 vs mu">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(H~%2C%20W~)%2C%20tanb%20%3D%2010%2C%20M2%20vs%20mu">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{H},~\tilde{G})$ model: <ul> <li><a href="104458?version=1&table=Exp limit on (H~, G~)">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(H~%2C%20G~)">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(H~%2C%20G~)">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (H~, G~)">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(H~%2C%20G~)">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(H~%2C%20G~)">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{H},~\tilde{a})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{a})=100\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (H~, a~) B(N1->Za~) = 100%">Expected limit</a> <li><a href="104458?version=1&table=Exp%20limit%20(%2B1sig)%20on%20(H~%2C%20a~)%20B(N1-%3EZa~)%20%3D%20100%25">Expected limit ($+1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Exp%20limit%20(-1sig)%20on%20(H~%2C%20a~)%20B(N1-%3EZa~)%20%3D%20100%25">Expected limit ($-1\sigma_{\textrm{exp}}$)</a> <li><a href="104458?version=1&table=Obs limit on (H~, a~) B(N1->Za~) = 100%">Observed limit</a> <li><a href="104458?version=1&table=Obs%20limit%20(%2B1sig)%20on%20(H~%2C%20a~)%20B(N1-%3EZa~)%20%3D%20100%25">Observed limit ($+1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> <li><a href="104458?version=1&table=Obs%20limit%20(-1sig)%20on%20(H~%2C%20a~)%20B(N1-%3EZa~)%20%3D%20100%">Observed limit ($-1\sigma_{\textrm{theory}}^{\textrm{SUSY}}$)</a> </ul> <li>$(\tilde{H},~\tilde{a})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{a})=75\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (H~, a~) B(N1->Za~) = 75%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (H~, a~) B(N1->Za~) = 75%">Observed limit</a> </ul> <li>$(\tilde{H},~\tilde{a})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{a})=50\%$): <ul> <li><a href="104458?version=1&table=Exp limit on (H~, a~) B(N1->Za~) = 50%">Expected limit</a> <li><a href="104458?version=1&table=Obs limit on (H~, a~) B(N1->Za~) = 50%">Observed limit</a> </ul> <li>$(\tilde{H},~\tilde{a})$ model ($\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{a})=25\%$): <ul> <li>Expected limit : (No mass point could be excluded) <li><a href="104458?version=1&table=Obs limit on (H~, a~) B(N1->Za~) = 25%">Observed limit</a> </ul> </ul> <b>EWKino branching ratios:</b> <ul> <li>$(\tilde{W},~\tilde{H})$ model: <ul> <li><a href="104458?version=1&table=B(C2-%3EW%2BN1%2CN2)%20in%20(W~%2C%20H~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow W\tilde{\chi}_{1,2}^{0})$</a> <li><a href="104458?version=1&table=B(C2-%3EZ%2BC1)%20in%20(W~%2C%20H~)%2C%20tanb=10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow Z\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(C2-%3Eh%2BC1)%20in%20(W~%2C%20H~)%2C%20tanb=10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow h\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(N3-%3EW%2BC1)%20in%20(W~%2C%20H~)%2C%20tanb=10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow W\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(N3-%3EZ%2BN1%2CN2)%20in%20(W~%2C%20H~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow Z\tilde{\chi}_{1,2}^{0})$</a> <li><a href="104458?version=1&table=B(N3-%3Eh%2BN1%2CN2)%20in%20(W~%2C%20H~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow h\tilde{\chi}_{1,2}^{0})$</a> </ul> <li>$(\tilde{H},~\tilde{W})$ model: <ul> <li><a href="104458?version=1&table=B(C2-%3EW%2BN1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow W\tilde{\chi}_{1}^{0})$</a> <li><a href="104458?version=1&table=B(C2-%3EZ%2BC1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow Z\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(C2-%3Eh%2BC1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{\pm}\rightarrow h\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(N2-%3EW%2BC1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow W\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(N2-%3EZ%2BN1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})$</a> <li><a href="104458?version=1&table=B(N2-%3Eh%2BN1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{2}^{0}\rightarrow h\tilde{\chi}_{1}^{0})$</a> <li><a href="104458?version=1&table=B(N3-%3EW%2BC1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow W\tilde{\chi}_{1}^{\pm})$</a> <li><a href="104458?version=1&table=B(N3-%3EZ%2BN1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow Z\tilde{\chi}_{1}^{0})$</a> <li><a href="104458?version=1&table=B(N3-%3Eh%2BN1)%20in%20(H~%2C%20W~)%2C%20tanb%3D10%2C%20mu%3E0">$\textrm{B}(\tilde{\chi}_{3}^{0}\rightarrow h\tilde{\chi}_{1}^{0})$</a> </ul> </ul> <b>Cross-section upper limit:</b> <ul> <li>Expected: <ul> <li><a href="104458?version=1&table=Expected cross-section upper limit on C1C1-WW">$(\tilde{W},~\tilde{B})$-SIM model (C1C1-WW)</a> <li><a href="104458?version=1&table=Expected cross-section upper limit on C1N2-WZ">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ)</a> <li><a href="104458?version=1&table=Expected cross-section upper limit on C1N2-Wh">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-Wh)</a> <li><a href="104458?version=1&table=Expected cross-section upper limit on (H~, G~)">$(\tilde{H},~\tilde{G})$ model</a> </ul> <li>Observed: <ul> <li><a href="104458?version=1&table=Observed cross-section upper limit on C1C1-WW">$(\tilde{W},~\tilde{B})$-SIM model (C1C1-WW)</a> <li><a href="104458?version=1&table=Observed cross-section upper limit on C1N2-WZ">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ)</a> <li><a href="104458?version=1&table=Observed cross-section upper limit on C1N2-Wh">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-Wh)</a> <li><a href="104458?version=1&table=Observed cross-section upper limit on (H~, G~)">$(\tilde{H},~\tilde{G})$ model</a> </ul> </ul> <b>Acceptance:</b> <ul> <li><a href="104458?version=1&table=Acceptance of C1C1-WW signals by SR-4Q-VV">$(\tilde{W},~\tilde{B})$-SIM model (C1C1-WW) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Acceptance of C1N2-WZ signals by SR-4Q-VV">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Acceptance of C1N2-WZ signals by SR-2B2Q-VZ">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ) in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Acceptance of C1N2-Wh signals by SR-2B2Q-Vh">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Acceptance of N2N3-ZZ signals by SR-4Q-VV">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-ZZ) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Acceptance of N2N3-ZZ signals by SR-2B2Q-VZ">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-ZZ) in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Acceptance of N2N3-Zh signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-Zh) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Acceptance of N2N3-hh signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-hh) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Acceptance of (H~, G~) signals by SR-4Q-VV">$(\tilde{H},~\tilde{G})$ model in SR-4Q-VV</a> <li><a href="104458?version=1&table=Acceptance of (H~, G~) signals by SR-2B2Q-VZ">$(\tilde{H},~\tilde{G})$ model in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Acceptance of (H~, G~) signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{G})$ model in SR-2B2Q-Vh</a> </ul> <b>Efficiency:</b> <ul> <li><a href="104458?version=1&table=Efficiency of C1C1-WW signals by SR-4Q-VV">$(\tilde{W},~\tilde{B})$-SIM model (C1C1-WW) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Efficiency of C1N2-WZ signals by SR-4Q-VV">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Efficiency of C1N2-WZ signals by SR-2B2Q-VZ">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-WZ) in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Efficiency of C1N2-Wh signals by SR-2B2Q-Vh">$(\tilde{W},~\tilde{B})$-SIM model (C1N2-Wh) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Efficiency of N2N3-ZZ signals by SR-4Q-VV">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-ZZ) in SR-4Q-VV</a> <li><a href="104458?version=1&table=Efficiency of N2N3-ZZ signals by SR-2B2Q-VZ">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-ZZ) in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Efficiency of N2N3-Zh signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-Zh) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Efficiency of N2N3-hh signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{B})$-SIM model (N2N3-hh) in SR-2B2Q-Vh</a> <li><a href="104458?version=1&table=Efficiency of (H~, G~) signals by SR-4Q-VV">$(\tilde{H},~\tilde{G})$ model in SR-4Q-VV</a> <li><a href="104458?version=1&table=Efficiency of (H~, G~) signals by SR-2B2Q-VZ">$(\tilde{H},~\tilde{G})$ model in SR-2B2Q-VZ</a> <li><a href="104458?version=1&table=Efficiency of (H~, G~) signals by SR-2B2Q-Vh">$(\tilde{H},~\tilde{G})$ model in SR-2B2Q-Vh</a> </ul>

Cut flows of some representative signals up to SR-4Q-VV, SR-2B2Q-VZ, and SR-2B2Q-Vh. One signal point from the $(\tilde{W},~\tilde{B})$ simplified models (C1C1-WW, C1N2-WZ, and C1N2-Wh) and $(\tilde{H},~\tilde{G})$ is chosen. The "preliminary event reduction" is a technical selection applied for reducing the sample size, which is fully efficient after the $n_{\textrm{Large}-R~\textrm{jets}}\geq 2$ selection.

The boson-tagging efficiency for jets arising from $W/Z$ bosons decaying into $q\bar{q}$ (signal jets) are shown. The signal jet efficiency of $W_{qq}$/$Z_{qq}$-tagging is evaluated using a sample of pre-selected large-$R$ jets ($p_{\textrm{T}}>200~\textrm{GeV}, |\eta|<2.0, m_{J} > 40~\textrm{GeV}$) in the simulated $(\tilde{W},\tilde{B})$ simplified model signal events with $\Delta m (\tilde{\chi}_{\textrm{heavy}},~\tilde{\chi}_{\textrm{light}}) \ge 400~\textrm{GeV}$. The jets are matched with generator-level $W/Z$-bosons by $\Delta R<1.0$ which decay into $q\bar{q}$. The efficiency correction factors are applied on the signal efficiency rejection for the $W_{qq}$/$Z_{qq}$-tagging. The systematic uncertainty is represented by the hashed bands.

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Measurement of the production cross section of pairs of isolated photons in $pp$ collisions at 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
CERN-EP-2021-105, 2021.
Inspire Record 1887997 DOI 10.17182/hepdata.104925

A measurement of prompt photon-pair production in proton-proton collisions at $\sqrt{s}=13$ TeV is presented. The data were recorded by the ATLAS detector at the LHC with an integrated luminosity of 139 fb$^{-1}$. Events with two photons in the well-instrumented region of the detector are selected. The photons are required to be isolated and have a transverse momentum of $p_\mathrm{T,\gamma_{1(2)}} > 40(30)$ GeV for the leading (sub-leading) photon. The differential cross sections as functions of several observables for the diphoton system are measured and compared with theoretical predictions from state-of-the-art Monte Carlo and fixed-order calculations. The QCD predictions from next-to-next-to-leading-order calculations and multi-leg merged calculations are able to describe the measured integrated and differential cross sections within uncertainties, whereas lower-order calculations show significant deviations, demonstrating that higher-order perturbative QCD corrections are crucial for this process. The resummed predictions with parton showers additionally provide an excellent description of the low transverse-momentum regime of the diphoton system.

9 data tables

Differential cross section as a function of $p_{T,\gamma_{1}}$. The table contains the values measured in data and theory predictions from SHERPA, DIPHOX and NNLOJET.

Differential cross section as a function of $p_{T,\gamma_{2}}$. The table contains the values measured in data and theory predictions from SHERPA, DIPHOX and NNLOJET.

Integrated fiducial cross section measured in data and from different predictions.

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Search for exotic decays of the Higgs boson into long-lived particles in $pp$ collisions at $\sqrt{s} = 13$ TeV using displaced vertices in the ATLAS inner detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
2021.
Inspire Record 1882568 DOI 10.17182/hepdata.106655

A novel search for exotic decays of the Higgs boson into pairs of long-lived neutral particles, each decaying into a bottom quark pair, is performed using 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collision data collected with the ATLAS detector at the LHC. Events consistent with the production of a Higgs boson in association with a leptonically decaying $Z$ boson are analysed. Long-lived particle (LLP) decays are reconstructed from inner-detector tracks as displaced vertices with high mass and track multiplicity relative to Standard Model processes. The analysis selection requires the presence of at least two displaced vertices, effectively suppressing Standard Model backgrounds. The residual background contribution is estimated using a data-driven technique. No excess over Standard Model predictions is observed, and upper limits are set on the branching ratio of the Higgs boson to LLPs. Branching ratios above 10% are excluded at 95% confidence level for LLP mean proper lifetimes $c\tau$ as small as 4 mm and as large as 100 mm. For LLP masses below 40 GeV, these results represent the most stringent constraint in this lifetime regime.

7 data tables

95% CL exclusion limits on $\mathcal{B}(H\rightarrow aa \rightarrow b\bar{b}b\bar{b})$ for $m_a = 16$ GeV.

95% CL exclusion limits on $\mathcal{B}(H\rightarrow aa \rightarrow b\bar{b}b\bar{b})$ for $m_a = 25$ GeV.

95% CL exclusion limits on $\mathcal{B}(H\rightarrow aa \rightarrow b\bar{b}b\bar{b})$ for $m_a = 35$ GeV.

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Measurement of the $t\bar{t}t\bar{t}$ production cross section in $pp$ collisions at $\sqrt{s}$=13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
CERN-EP-2021-075, 2021.
Inspire Record 1869695 DOI 10.17182/hepdata.105039

A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb$^{-1}$ is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain $b$-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26$^{+17}_{-15}$ fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24$^{+7}_{-6}$ fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0$\pm$2.4 fb.

76 data tables

The results of the fitted signal strength $\mu$ in the 1L/2LOS channel

The results of fitted inclusive ${t\bar{t}t\bar{t}}$ cross-section in the 1L/2LOS channel

Ranking of the nuisance parameters included in the fit according to their impact on the signal strength $\mu$. The impact of each nuisance parameter, $\Delta\mu$, is computed by comparing the nominal best-fit value of $\mu$ with the result of the fit when fixing the nuisance parameter to its best-fit value, $\hat{\theta}$, shifted by its pre-fit (post-fit) uncertainties $\pm \Delta\theta$ ($\pm \Delta\hat{\theta}$).

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Search for charged-lepton-flavour violation in Z-boson decays with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale Charles ; et al.
Nature Phys. 17 (2021) 819-825, 2021.
Inspire Record 1865746 DOI 10.17182/hepdata.105516

A search for lepton-flavor-violating $Z\to e\tau$ and $Z\to\mu\tau$ decays with $pp$ collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139 fb$^{-1}$ of Run 2 $pp$ collisions at $\sqrt{s}=13$ TeV and is combined with the results of a similar ATLAS search in the final state in which the $\tau$-lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying $\tau$-leptons significantly improves the sensitivity reach for $Z\to\ell\tau$ decays. The $Z\to\ell\tau$ branching fractions are constrained in this analysis to $\mathcal{B}(Z\to e\tau)<7.0\times10^{-6}$ and $\mathcal{B}(Z\to \mu\tau)<7.2\times10^{-6}$ at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: $\mathcal{B}(Z\to e\tau)<5.0\times10^{-6}$ and $\mathcal{B}(Z\to \mu\tau)<6.5\times10^{-6}$ at 95% confidence level.

16 data tables

The best-fit predicted and observed distributions of the combined NN output in the low-$p_\text{T}$-SR for the $e\tau_\mu$ channel. The first and last bin include underflow and overflow events, respectively.

The best-fit predicted and observed distributions of the combined NN output in the low-$p_\text{T}$-SR for the $\mu\tau_e$ channel. The first and last bin include underflow and overflow events, respectively.

The best-fit predicted and observed distributions of the combined NN output in the high-$p_\text{T}$-SR for the $e\tau_\mu$ channel. The first and last bin include underflow and overflow events, respectively.

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Version 2
Measurements of the inclusive and differential production cross sections of a top-quark-antiquark pair in association with a $Z$ boson at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 81 (2021) 737, 2021.
Inspire Record 1853014 DOI 10.17182/hepdata.100351

Measurements of both the inclusive and differential production cross sections of a top-quark-antiquark pair in association with a $Z$ boson ($t\bar{t}Z$) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on $\sqrt{s} = 13$ TeV proton-proton collision data with an integrated luminosity of 139 fb$^{-1}$, recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be $\sigma_{t\bar{t}Z} = 0.99 \pm 0.05$ (stat.) $\pm 0.08$ (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the $t\bar{t}Z$ system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a $\chi^{2}/$ndf and $p$-value computation. Overall, good agreement is observed between the unfolded data and the predictions.

76 data tables

The measured $t\bar{t}\text{Z}$ cross-section value and its uncertainty based on the fit results from the combined trilepton and tetralepton channels. The value corresponds to the phase-space region where the difermion mass from the Z boson decay lies in the range $70 < m_{f\bar{f}} < 110$ GeV.

List of relative uncertainties of the measured inclusive $t\bar{t}\text{Z}$ cross section from the combined fit. The uncertainties are symmetrised for presentation and grouped into the categories described in the text. The quadratic sum of the individual uncertainties is not equal to the total uncertainty due to correlations introduced by the fit.

The definitions of the trilepton signal regions: for the inclusive measurement, a combination of the regions with pseudo-continuous $b$-tagging 3$\ell$-Z-1$b$4$j$-PCBT and 3$\ell$-Z-2$b$3$j$-PCBT is used, whereas for the differential measurement, only the region 3$\ell$-Z-2$b$3$j$, with a fixed $b$-tagging WP is employed.

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Measurements of $W^+W^-+\ge 1~$jet production cross-sections in $pp$ collisions at $\sqrt{s}=13~$TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale Charles ; et al.
JHEP 06 (2021) 003, 2021.
Inspire Record 1852328 DOI 10.17182/hepdata.100511

Fiducial and differential measurements of $W^+W^-$ production in events with at least one hadronic jet are presented. These cross-section measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton$-$proton collision data collected at $\sqrt{s}=13~$TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139$~$fb$^{-1}$. Events are selected with exactly one oppositely charged electron$-$muon pair and at least one hadronic jet with a transverse momentum of $p_{\mathrm{T}}>30~$GeV and a pseudorapidity of $|\eta|<4.5$. After subtracting the background contributions and correcting for detector effects, the jet-inclusive $W^+W^-+\ge 1~$jet fiducial cross-section and $W^+W^-+$ jets differential cross-sections with respect to several kinematic variables are measured, thus probing a previously unexplored event topology at the LHC. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the $W^+W^-$ system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced.

55 data tables

Measured fiducial cross section for $pp\rightarrow W^+W^-$+jets production. The second column contains the results obtained with a fiducial particle phase space that includes a veto on $b$-jets. This alternative result is obtained from the nominal result by the application of bin-wise correction that is calculated as the ratio of the predicted differential cross-section in the nominal analysis phase space and the predicted cross-section for a phase space that includes a veto on events with $b$-jets with $p_{\mathrm{T}} > 20$ GeV. Also shown are the Standard Model predictions for $q\bar{q} \rightarrow WW$, obtained from Sherpa 2.2.2, MadGraph 2.3.3 + Pythia 8.212 using FxFx merging, and Powheg MiNLO + Pythia 8.244. These predictions are supplemented by the Sherpa 2.2.2 + OpenLoops simulation of $gg\rightarrow WW$. Finally, the prediction from MATRIX is given, which includes nNLO QCD and NLO EW corrections to $WW$+jet production.

Measured fiducial cross section for $pp\rightarrow W^+W^-$+jets production for the observable $p_{\mathrm{T}}^{\mathrm{lead.~lep.}}$. The second column contains the results obtained with a fiducial particle phase space that includes a veto on $b$-jets. This alternative result is obtained from the nominal result by the application of bin-wise correction that is calculated as the ratio of the predicted differential cross-section in the nominal analysis phase space and the predicted cross-section for a phase space that includes a veto on events with $b$-jets with $p_{\mathrm{T}} > 20$ GeV. Also shown are the Standard Model predictions for $q\bar{q} \rightarrow WW$, obtained from Sherpa 2.2.2, MadGraph 2.3.3 + Pythia 8.212 using FxFx merging, and Powheg MiNLO + Pythia 8.244. These predictions are supplemented by the Sherpa 2.2.2 + OpenLoops simulation of $gg\rightarrow WW$. Finally, the prediction from MATRIX is given, which includes nNLO QCD and NLO EW corrections to $WW$+jet production. Overflow events are included in the last bin. The largest observed value is 1168 GeV.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T}}^{\mathrm{lead.~lep.}}$

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