Version 2
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Phys.Rev.D 101 (2020) 072001, 2020.
Inspire Record 1771533 DOI 10.17182/hepdata.91127

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell $W$ and $Z$ bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of $\sqrt{s}$ = 13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015-2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full dataset are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV.

58 data tables match query

Distributions in SR-low of the data and post-fit background prediction for m<sub>T</sub>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt&#772;, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.

Distributions in SR-low of the data and post-fit background prediction for m<sub>T</sub>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt&#772;, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.

Distributions in SR-low of the data and post-fit background prediction for H<sup>boost</sup>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt&#772;, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.

More…

Version 4
Search for squarks and gluinos in final states with same-sign leptons and jets using 139 fb$^{-1}$ of data collected with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 06 (2020) 046, 2020.
Inspire Record 1754675 DOI 10.17182/hepdata.91214

A search for supersymmetric partners of gluons and quarks is presented, involving signatures with jets and either two isolated leptons (electrons or muons) with the same electric charge, or at least three isolated leptons. A data sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to a total integrated luminosity of 139 fb$^{-1}$, is used for the search. No significant excess over the Standard Model expectation is observed. The results are interpreted in simplified supersymmetric models featuring both R-parity conservation and R-parity violation, raising the exclusion limits beyond those of previous ATLAS searches to 1600 GeV for gluino masses and 750 GeV for bottom and top squark masses in these scenarios.

120 data tables match query

Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.

Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.

Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.

More…

Dijet azimuthal correlations and conditional yields in $pp$ and $p$+Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.C 100 (2019) 034903, 2019.
Inspire Record 1717481 DOI 10.17182/hepdata.93905

This paper presents a measurement of forward-forward and forward-central dijet azimuthal angular correlations and conditional yields in proton-proton ($pp$) and proton-lead ($p$+Pb) collisions as a probe of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering is low. In these regions, gluon saturation can modify the rapidly increasing parton distribution function of the gluon. The analysis utilizes 25 pb$^{-1}$ of $pp$ data and 360 $\mu \mathrm{b}^{-1}$ of $p$+Pb data, both at $\sqrt{s_{\rm NN}}$ = 5.02 TeV, collected in 2015 and 2016, respectively, with the ATLAS detector at the LHC. The measurement is performed in the center-of-mass frame of the nucleon-nucleon system in the rapidity range between $-$4.0 and 4.0 using the two highest transverse momentum jets in each event, with the highest transverse momentum jet restricted to the forward rapidity range. No significant broadening of azimuthal angular correlations is observed for forward-forward or forward-central dijets in $p$+Pb compared to $pp$ collisions. For forward-forward jet pairs in the proton-going direction, the ratio of conditional yields in $p$+Pb collisions to those in $pp$ collisions is suppressed by approximately 20%, with no significant dependence on the transverse momentum of the dijet system. No modification of conditional yields is observed for forward-central dijets.

11 data tables match query

Unfolded azimuthal angular correlation distributions. Black markers represent p+Pb, red markers p+p

Unfolded width of azimuthal angular correlation distributions. Full markers represent p+Pb, open markers p+p

Unfolded Dijet conditional yields. Full markers represent p+Pb, open markers p+p

More…

Search for new phenomena in events with an energetic jet and missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Phys.Rev.D 103 (2021) 112006, 2021.
Inspire Record 1847779 DOI 10.17182/hepdata.102093

Results of a search for new physics in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 139 fb$^{-1}$ at a center-of-mass energy of 13 TeV collected in the period 2015-2018 with the ATLAS detector at the Large Hadron Collider. Compared to previous publications, in addition to an increase of almost a factor of four in the data size, the analysis implements a number of improvements in the signal selection and the background determination leading to enhanced sensitivity. Events are required to have at least one jet with transverse momentum above 150 GeV and no reconstructed leptons ($e$, $\mu$ or $\tau$) or photons. Several signal regions are considered with increasing requirements on the missing transverse momentum starting at 200 GeV. Overall agreement is observed between the number of events in data and the Standard Model predictions. Model-independent 95 % confidence-level limits on visible cross sections for new processes are obtained in the range between 736 fb and 0.3 fb with increasing missing transverse momentum. Results are also translated into improved exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, supersymmetric particles in several compressed scenarios, axion-like particles, and new scalar particles in dark-energy-inspired models. In addition, the data are translated into bounds on the invisible branching ratio of the Higgs boson.

98 data tables match query

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Post-fit $p_{\mathrm{T}}^{\mathrm{recoil}}$ distribution:</b> <ul> <li><a href="102093?version=1&table=HistogramCR1mu0b">CR1mu0b</a> <li><a href="102093?version=1&table=HistogramCR1e0b">CR1e0b</a> <li><a href="102093?version=1&table=HistogramCR1L1b">CR1L1b</a> <li><a href="102093?version=1&table=HistogramCR2mu">CR2mu</a> <li><a href="102093?version=1&table=HistogramCR2e">CR2e</a> <li><a href="102093?version=1&table=HistogramSR">SR</a> </ul> <b>Exclusion contours:</b> <ul> <li>Dark Matter axial-vector mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMA">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMA">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMA">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMA">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMA">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMA">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMA">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMA">-2 $\sigma$ expected</a> </ul> <li>Dark Matter pseudo-scalar mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMP">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMP">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMP">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMP">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMP">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMP">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMP">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMP">-2 $\sigma$ expected</a> </ul> <li>Dark Matter vector mediator: <ul> <li><a href="102093?version=1&table=ContourobsDMV">observed</a> <li><a href="102093?version=1&table=Contourobs_p1DMV">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourobs_m1DMV">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=ContourexpDMV">expected</a> <li><a href="102093?version=1&table=Contourexp_p1DMV">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m1DMV">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_p2DMV">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourexp_m2DMV">-2 $\sigma$ expected</a> </ul> <li>Dark Matter spin-dependent WIMP-nucleon scattering cross-section: <a href="102093?version=1&table=ContourSDneutron">observed</a> <li>Dark Matter spin-independent WIMP-nucleon scattering cross-section: <a href="102093?version=1&table=ContourSInucleon">observed</a> <li>Dark Matter WIMP annihilation rate: <a href="102093?version=1&table=ContourID">observed</a> <li>SUSY stop pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsTT_directCC">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1TT_directCC">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1TT_directCC">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expTT_directCC">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1TT_directCC">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1TT_directCC">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2TT_directCC">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2TT_directCC">-2 $\sigma$ expected</a> </ul> <li>SUSY stop pair production (4-body decay): <ul> <li><a href="102093?version=1&table=Contourg_obsTT_bffN">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1TT_bffN">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1TT_bffN">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expTT_bffN">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1TT_bffN">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1TT_bffN">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2TT_bffN">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2TT_bffN">-2 $\sigma$ expected</a> </ul> <li>SUSY sbottom pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsBB">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1BB">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1BB">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expBB">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1BB">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1BB">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2BB">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2BB">-2 $\sigma$ expected</a> </ul> <li>SUSY squark pair production: <ul> <li><a href="102093?version=1&table=Contourg_obsSS">observed</a> <li><a href="102093?version=1&table=Contourg_obs_p1SS">+1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_obs_m1SS">-1 $\sigma_{\mathrm{theory}}^{\mathrm{PDF+scale}}$ observed</a> <li><a href="102093?version=1&table=Contourg_expSS">expected</a> <li><a href="102093?version=1&table=Contourg_exp_p1SS">+1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m1SS">-1 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_p2SS">+2 $\sigma$ expected</a> <li><a href="102093?version=1&table=Contourg_exp_m2SS">-2 $\sigma$ expected</a> </ul> <li>Dark energy: <a href="102093?version=1&table=ContourDE">observed and expected</a> <li>ADD: <a href="102093?version=1&table=ContourADD">observed and expected</a> <li>Axion-like particles: <a href="102093?version=1&table=ContourALPs">observed and expected</a> </ul> <b>Impact of systematic uncertainties:</b> <a href="102093?version=1&table=Tablesystimpacts">Table</a><br/><br/> <b>Yields of exclusive regions:</b> <a href="102093?version=1&table=TableyieldsEM0">EM0</a> <a href="102093?version=1&table=TableyieldsEM1">EM1</a> <a href="102093?version=1&table=TableyieldsEM2">EM2</a> <a href="102093?version=1&table=TableyieldsEM3">EM3</a> <a href="102093?version=1&table=TableyieldsEM4">EM4</a> <a href="102093?version=1&table=TableyieldsEM5">EM5</a> <a href="102093?version=1&table=TableyieldsEM6">EM6</a> <a href="102093?version=1&table=TableyieldsEM7">EM7</a> <a href="102093?version=1&table=TableyieldsEM8">EM8</a> <a href="102093?version=1&table=TableyieldsEM9">EM9</a> <a href="102093?version=1&table=TableyieldsEM10">EM10</a> <a href="102093?version=1&table=TableyieldsEM11">EM11</a> <a href="102093?version=1&table=TableyieldsEM12">EM12</a><br/><br/> <b>Yields of inclusive regions:</b> <a href="102093?version=1&table=TableyieldsIM0">IM0</a> <a href="102093?version=1&table=TableyieldsIM1">IM1</a> <a href="102093?version=1&table=TableyieldsIM2">IM2</a> <a href="102093?version=1&table=TableyieldsIM3">IM3</a> <a href="102093?version=1&table=TableyieldsIM4">IM4</a> <a href="102093?version=1&table=TableyieldsIM5">IM5</a> <a href="102093?version=1&table=TableyieldsIM6">IM6</a> <a href="102093?version=1&table=TableyieldsIM7">IM7</a> <a href="102093?version=1&table=TableyieldsIM8">IM8</a> <a href="102093?version=1&table=TableyieldsIM9">IM9</a> <a href="102093?version=1&table=TableyieldsIM10">IM10</a> <a href="102093?version=1&table=TableyieldsIM11">IM11</a> <a href="102093?version=1&table=TableyieldsIM12">IM12</a><br/><br/> <b>Cutflows:</b><br/><br/> Signals filtered with a truth $E_\mathrm{T}^\mathrm{miss}$ cut at: <ul> <li> <a href="102093?version=1&table=Tablecutflows150GeV">150 GeV</a> <li> <a href="102093?version=1&table=Tablecutflows350GeV">350 GeV</a> </ul>

The measured $p_{\mathrm{T}}^{\mathrm{recoil}}$ distributions in the $W \rightarrow \mu \nu $ control region, compared with the background predictions as estimated after the simultaneous, binned background-only fit to the data in the control regions. The last bin of the distribution contains overflows.

The measured $p_{\mathrm{T}}^{\mathrm{recoil}}$ distributions in the $W \rightarrow e \nu$ control region, compared with the background predictions as estimated after the simultaneous, binned background-only fit to the data in the control regions. The last bin of the distribution contains overflows.

More…

Search for doubly and singly charged Higgs bosons decaying into vector bosons in multi-lepton final states with the ATLAS detector using proton-proton collisions at $\sqrt{s}$ = 13 TeV

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 06 (2021) 146, 2021.
Inspire Record 1843269 DOI 10.17182/hepdata.97160

A search for charged Higgs bosons decaying into $W^\pm W^\pm$ or $W^\pm Z$ bosons is performed, involving experimental signatures with two leptons of the same charge, or three or four leptons with a variety of charge combinations, missing transverse momentum and jets. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb$^{-1}$. The search is guided by a type-II seesaw model that extends the scalar sector of the Standard Model with a scalar triplet, leading to a phenomenology that includes doubly and singly charged Higgs bosons. Two scenarios are explored, corresponding to the pair production of doubly charged $H^{\pm\pm}$ bosons, or the associated production of a doubly charged $H^{\pm\pm}$ boson and a singly charged $H^\pm$ boson. No significant deviations from the Standard Model predictions are observed. $H^{\pm\pm}$ bosons are excluded at 95% confidence level up to 350 GeV and 230 GeV for the pair and associated production modes, respectively.

25 data tables match query

Distribution of $E_{T}^{miss}$, which is one of the discriminating variables used to define the $2\ell^{sc}$ SRs. The events are selected with the preselection requirements listed in Table 4 in the paper. The data (dots) are compared with the expected contributions from the relevant background sources (histograms). The expected signal distributions for $m_{H^{\pm\pm}} = 300~GeV$ are also shown, scaled to the observed number of events. The last bin includes overflows.

Distribution of $\Delta R_{\ell^{\pm}\ell^{\pm}}$, which is one of the discriminating variables used to define the $2\ell^{sc}$ SRs. The events are selected with the preselection requirements listed in Table 4 in the paper. The data (dots) are compared with the expected contributions from the relevant background sources (histograms). The expected signal distributions for $m_{H^{\pm\pm}} = 300~GeV$ are also shown, scaled to the observed number of events. The last bin includes overflows.

Distribution of $M_{jets}$, which is one of the discriminating variables used to define the $2\ell^{sc}$ SRs. The events are selected with the preselection requirements listed in Table 4 in the paper. The data (dots) are compared with the expected contributions from the relevant background sources (histograms). The expected signal distributions for $m_{H^{\pm\pm}} = 300~GeV$ are also shown, scaled to the observed number of events. The last bin includes overflows.

More…

Version 2
Search for squarks and gluinos in final states with jets and missing transverse momentum using 139 fb$^{-1}$ of $\sqrt{s}$ =13 TeV $pp$ collision data with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 02 (2021) 143, 2021.
Inspire Record 1827025 DOI 10.17182/hepdata.95664

A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. The results are interpreted in the context of various $R$-parity-conserving models where squarks and gluinos are produced in pairs or in association and a neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.30 TeV for a simplified model containing only a gluino and the lightest neutralino, assuming the latter is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.85 TeV are excluded if the lightest neutralino is massless. These limits extend substantially beyond the region of supersymmetric parameter space excluded previously by similar searches with the ATLAS detector.

150 data tables match query

Observed $m_{\mathrm{eff}}$ distributions in signal regions MB-SSd. The histograms show the MC background predictions normalised by the background-only fit. The hatched (red) error bands indicate experimental and MC statistical uncertainties. Expected distributions for benchmark signal model points, normalised using the approximate NNLO+NNLL cross-section times integrated luminosity, are also shown for comparison (masses in GeV).

Observed $m_{\mathrm{eff}}$ distributions in signal regions MB-SSd. The histograms show the MC background predictions normalised by the background-only fit. The hatched (red) error bands indicate experimental and MC statistical uncertainties. Expected distributions for benchmark signal model points, normalised using the approximate NNLO+NNLL cross-section times integrated luminosity, are also shown for comparison (masses in GeV).

Observed metSig distributions in signal regions MB-SSd. The histograms show the MC background predictions normalised by the background-only fit. The hatched (red) error bands indicate experimental and MC statistical uncertainties. Expected distributions for benchmark signal model points, normalised using the approximate NNLO+NNLL cross-section times integrated luminosity, are also shown for comparison (masses in GeV).

More…

Search for new phenomena in events with two opposite-charge leptons, jets and missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 04 (2021) 165, 2021.
Inspire Record 1844425 DOI 10.17182/hepdata.98627

The results of a search for direct pair production of top squarks and for dark matter in events with two opposite-charge leptons (electrons or muons), jets and missing transverse momentum are reported, using 139 fb$^{-1}$ of integrated luminosity from proton-proton collisions at $\sqrt{s} = 13$ TeV, collected by the ATLAS detector at the Large Hadron Collider during Run 2 (2015-2018). This search considers the pair production of top squarks and is sensitive across a wide range of mass differences between the top squark and the lightest neutralino. Additionally, spin-0 mediator dark-matter models are considered, in which the mediator is produced in association with a pair of top quarks. The mediator subsequently decays to a pair of dark-matter particles. No significant excess of events is observed above the Standard Model background, and limits are set at 95% confidence level. The results exclude top squark masses up to about 1 TeV, and masses of the lightest neutralino up to about 500 GeV. Limits on dark-matter production are set for scalar (pseudoscalar) mediator masses up to about 250 (300) GeV.

196 data tables match query

Two-body selection. Distributions of $m_{T2}$ in $SR^{2-body}_{110,\infty}$ for (a) different-flavour and (b) same-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference dark-matter signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction.

Two-body selection. Distributions of $m_{T2}$ in $SR^{2-body}_{110,\infty}$ for (a) different-flavour and (b) same-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference dark-matter signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction.

Three-body selection. Distributions of $M_{\Delta}^R$ in (a,b) $SR_{W}^{3-body}$ and (c,d) $SR_{T}^{3-body}$ for (left) same-flavour and (right) different-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction; red arrows show data outside the vertical-axis range.

More…

Search for pair production of scalar leptoquarks decaying into first- or second-generation leptons and top quarks in proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 81 (2021) 313, 2021.
Inspire Record 1821703 DOI 10.17182/hepdata.96389

A search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in $B$ meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-$p_{\mathrm{T}}$ large-radius jet. The full Run 2 dataset is exploited, consisting of 139 fb$^{-1}$ of data collected from proton-proton collisions at $\sqrt{s}=13$ TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at 1480 GeV and 1470 GeV for the electron and muon channel, respectively.

4 data tables match query

Expected and observed upper limits at the 95% CL on the leptoquark pair production cross section as a function of leptoquark mass under the assumption of $\mathcal{B}$(LQ->$te$)=1.

Expected and observed upper limits at the 95% CL on the leptoquark pair production cross section as a function of leptoquark mass under the assumption of $\mathcal{B}$(LQ->$t\mu$)=1.

Expected and observed 95% CL lower limits on the leptoquark mass as a function of the branching ratio $\mathcal{B}$(LQ->$te$).

More…

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

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Nature Phys. 17 (2021) 819 819-825, 2021.
Inspire Record 1821688 DOI 10.17182/hepdata.96390

The ATLAS experiment at the Large Hadron Collider reports a search for charged-lepton-flavour violation in decays of $Z$ bosons into a τ lepton and an electron or muon of opposite charge.

9 data tables match query

The best-fit expected and observed distributions of the combined NN output in the CRZ$\tau\tau$ for the $\mu\tau$ channel for events with 1-prong $\tau_\text{had-vis}$ candidates. The last bin in each plot includes overflow events.

The best-fit expected and observed distributions of the combined NN output in the CRZ$\tau\tau$ for the $\mu\tau$ channel for events with 3-prong $\tau_\text{had-vis}$ candidates. The last bin in each plot includes overflow events.

The best-fit expected and observed distributions of the combined NN output in the VRSS for the $e\tau$ channel for events with 1-prong $\tau_\text{had-vis}$ candidates. The last bin in each plot includes overflow events.

More…

Search for dark matter produced in association with a dark Higgs boson decaying into $W^\pm W^\mp$ or $ZZ$ in fully hadronic final states from $\sqrt{s}=13$ TeV $pp$ collisions recorded with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Phys.Rev.Lett. 126 (2021) 121802, 2021.
Inspire Record 1822529 DOI 10.17182/hepdata.97191

Several extensions of the Standard Model predict the production of dark matter particles at the LHC. An uncharted signature of dark matter particles produced in association with $VV=W^\pm W^\mp$ or $ZZ$ pairs from a decay of a dark Higgs boson $s$ is searched for using 139 fb$^{-1}$ of $pp$ collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. The $s\to V(q\bar q)V(q\bar q)$ decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted $VV$ pairs using jets in the calorimeter and tracking information. Dark Higgs scenarios with $m_s > 160$ GeV are excluded.

13 data tables match query

Data overlaid on SM background post-fit yields stacked in each SR and CR category and E<sub>T</sub><sup>miss</sup> bin with the maximum-likelihood estimators set to the conditional values of the CR-only fit, and propagated to SR and CRs. Pre-fit uncertainties cover differences between the data and pre-fit background prediction.

Dominant sources of uncertainty for three dark Higgs scenarios after the fit to Asimov data generated from the expected values of the maximum-likelihood estimators including predicted signals with m<sub>Z'</sub> = 1 TeV and m<sub>s</sub> of (a) 160 GeV, (b) 235 GeV, and (c) 310 GeV. The uncertainty in the fitted signal yield relative to the theory prediction is presented. Total is the quadrature sum of statistical and total systematic uncertainties, which consider correlations.

The ratios (&mu;) of the 95&#37; C.L. upper limits on the combined s&rarr; W<sup>&plusmn;</sup>W<sup>&#8723;</sup> and s&rarr; ZZ cross section to simplified model expectations for the m<sub>Z'</sub>=0.5 TeV scenario, for various m<sub>s</sub> hypotheses. The observed limits (solid line) are consistent with the expectation under the SM-only hypothesis (dashed line) within uncertainties (filled band), except for a small excess for m<sub>s</sub>=160 GeV, discussed in the text.

More…