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CERN-LHC. Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at $\sqrt{s}$ = 8 TeV corresponding to an integrated luminosity of 20.3 fb$^{-1}$ collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios. Upper limits (95% CL) from the DV+$E_T^{miss}$ channel on the production cross-section and the corresponding event-level efficiencies (from Auxiliary Figure 9a) for two GGM SUSY models as a function of the $\tilde{\chi}_1^0$ proper decay distance $c\tau$. The models consider gluino pair production, with $\tilde{g}\to qq[\tilde{\chi}_1^0\to Z\tilde{G}]$ decays, $m(\tilde{g})$ = 1100 GeV and a $\tilde{\chi}_1^0$ mass in GeV as indicated. For comparison, the production cross-section for $m(\tilde{g})$ = 1100 GeV is $7.6\pm2.8$ fb.

CERN-LHC. A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in $\sqrt{s}=13\mathrm{\ Te\kern -0.1em V}$ proton--proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. The results are interpreted in the context of various models where squarks and gluinos are pair-produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.03$\mathrm{\ Te\kern -0.1em V}$ for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.55$\mathrm{\ Te\kern -0.1em V}$ are excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector. Signal region efficiency for simplified model with squark pair production and direct decays to a quark and neutralino in SR RJR-C2.

CERN-LHC, ATLAS. A search for a right-handed gauge boson WR, decaying into a boosted right-handed heavy neutrino NR, in the framework of Left-Right Symmetric Models is presented. It is based on data from proton-proton collisions with a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider during the years 2015, 2016 and 2017, corresponding to an integrated luminosity of 80 fb−1. The search is performed separately for electrons and muons in the final state. A distinguishing feature of the search is the use of large-radius jets containing electrons. Selections based on the signal topology result in smaller background compared with to expected signal. No significant deviation from the Standard Model prediction is observed and lower limits are set in the WR and NR mass plane. Mass values of the WR smaller than 3.8-5 TeV are excluded for NR in the mass range 0.1-1.8 TeV. Expected 95% CL exclusion contours in the $(m_{N_R}, m_{W_R})$ plane in the electron channel.

The combined $\tilde\chi^{\pm}_{1}\tilde\chi^{\mp}_{1} + \tilde\chi^{\pm}_{1}\tilde\chi^{0}_{1}$ reconstruction efficiencies in the SRFR region. Results are given as a function of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ mass and branching fraction to Z bosons, and are derived separately when requiring that the charged-lepton decays of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ are into electrons only No data abstract available.

CERN-LHC. A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in $\sqrt{s}=13\mathrm{\ Te\kern -0.1em V}$ proton--proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. The results are interpreted in the context of various models where squarks and gluinos are pair-produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.03$\mathrm{\ Te\kern -0.1em V}$ for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.55$\mathrm{\ Te\kern -0.1em V}$ are excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector. Signal region acceptance for simplified model with squark pair production and direct decays to a quark and neutralino in SR Meff-2j-1600.

Exclusion curve for the simplified model of $\tilde\chi^{\pm}_{1}\tilde\chi^{\mp}_{1} + \tilde\chi^{0}_{1}\tilde\chi^{0}_{1}$ pair-production as a function of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ branching fraction to $Z$ and Higgs bosons. Results are shown for the charged-lepton decays of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ into electrons only for a mass of 700 GeV. The expected 95% CL exclusion (dashed black line) is shown with $\pm1~\sigma_{\mathrm{exp}}$ (yellow band) from systematic and statistical uncertainties on the expected yields. The observed 95% CL exclusion (solid red line) is shown with the $\pm1~\sigma_{\mathrm{theory}}^{\mathrm{SUSY}}$ (dotted red line) from signal cross section uncertainties on the signal models. The phase-space excluded by the search is shown in the shaded color. No data abstract available.

CERN-LHC. A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in $\sqrt{s}=13\mathrm{\ Te\kern -0.1em V}$ proton--proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. The results are interpreted in the context of various models where squarks and gluinos are pair-produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.03$\mathrm{\ Te\kern -0.1em V}$ for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.55$\mathrm{\ Te\kern -0.1em V}$ are excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector. Signal region efficiency for simplified model with squark pair production and decays to a quark and chargino in SR RJR-C4.

Exclusion curve for the simplified model of $\tilde\chi^{\pm}_{1}\tilde\chi^{\mp}_{1} + \tilde\chi^{0}_{1}\tilde\chi^{0}_{1}$ pair-production as a function of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ branching fraction to $Z$ and Higgs bosons. Results are shown for the charged-lepton decays of $\tilde\chi^{\pm}_{1}/\tilde\chi^{0}_{1}$ into muons only for a mass of 700 GeV. The expected 95% CL exclusion (dashed black line) is shown with $\pm1~\sigma_{\mathrm{exp}}$ (yellow band) from systematic and statistical uncertainties on the expected yields. The observed 95% CL exclusion (solid red line) is shown with the $\pm1~\sigma_{\mathrm{theory}}^{\mathrm{SUSY}}$ (dotted red line) from signal cross section uncertainties on the signal models. The phase-space excluded by the search is shown in the shaded color. No data abstract available.

CERN-LHC. A study of events in proton-proton collisions at a centre-of-mass energy of 7 TeV characterised by having large missing transverse momentum, jets and at least two tau leptons from a data sample of integrated luminosity 2 fb-1. The analysis finds no excesses above the Standard Model and presents lower limits on the GMSB breaking scale, Lambda, and the ratio of the vacuum expectation values of the two Higgs doublets, tan(beta). Data on the acceptances and efficiencies are given here taken from the auxilliary material linked below. The observed 95% CL limits on the minimal GMSB model parameters Lambda and tan(beta) over the tan(beta) region 42.8 to 48.8.

CERN-LHC. A search for additional heavy neutral Higgs bosons is performed using a data sample corresponding to an integrated luminosity of 139 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC. The 1l1tau_h channel fiducial region is defined as: - 1e+>=1tau_h or 1mu+>=1tau_h - ptLepton > 30 GeV - |etaMuon| < 2.4, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - ptTauVis > 25 GeV - |etaTauVis| < 2.3 (excluding 1.37 < |etaTauVis| < 1.52) - No events with more than 1 electron (ptEle > 15 GeV) or muon (ptMuon > 7 GeV, |etaMuon|<2.5) - If multiple tau_h exist, the leading visible pt one is chosen - l and tau_h opposite electric charge - |DeltaPhi(l,tau_h)| > 2.4 rad - mT(l,MET) < 40 GeV - veto 80 < m(l,tau_h) < 110 in 1e1tau_h channel The 2tau_h channel fiducial region is defined as: - >=2tau_h - ptTauVis > 65 GeV (at least one with ptTauVis > 130 GeV, note that technically, this upper threshold was 85 GeV for ~10% of the data) - No events with an electron or muon, ptLepton > 7 (15) GeV for muons (electrons), |etaMuon| < 2.5, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - If more than two tau_h exist, the two leading visible pt ones are chosen - The two tau_h have opposite electric charge - |DeltaPhi(tau1_h,tau2_h)| > 2.7 rad For Higgs interpretations events entering the fiducial region of each channel are categorised as: - "b-tag: if they contain a b-quark initiated jet (ptJet > 20 GeV, |etaJet|<2.5)" - "b-veto: otherwise" Observed two dimensional likelihood scan of the gluon-gluon fusion cross section times branching fraction, $\sigma(gg\phi)\times B(\phi\to\tau\tau)$, vs the b-associated production times branching fraction, $\sigma(bb\phi)\times B(\phi\to\tau\tau)$ for the scalar boson mass ($m_\phi$) indicated in the table. For each mass, 10000 points are scanned. At each point $\Delta(\mathrm{NLL})$ is calculated, defined as the negative-log-likelihood (NLL) of the conditional fit with $\sigma(gg\phi)$ and $\sigma(bb\phi)$ fixed to their values at the point and with the minimum NLL value at any point subtracted. The best-fit point and the preferred 68% and 95% boundaries are found at $2\Delta(\mathrm{NLL})$ values of 0.0, 2.30 and 5.90, respectively. The value of $2\Delta(\mathrm{NLL})$ for 200 GeV signal mass point is shown in the HEPData table.