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Search for new phenomena in events with three or more charged leptons in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The collaboration
JHEP 08 (2015) 138, 2015.

Abstract (data abstract)
CERN-LHC. A generic search for anomalous production of events with at least three charged leptons is presented. The data sample consists of $pp$ collisions at $\sqrt{s}=8$ TeV collected in 2012 by the ATLAS experiment at the CERN Large Hadron Collider, and corresponds to an integrated luminosity of 20.3 fb$^{-1}$. Events are required to have at least three selected lepton candidates, at least two of which must be electrons or muons, while the third may be a hadronically decaying tau. Selected events are categorized based on their lepton flavour content and signal regions are constructed using several kinematic variables of interest. No significant deviations from Standard Model predictions are observed. Model-independent upper limits on contributions from beyond the Standard Model phenomena are provided for each signal region, along with prescription to re-interpret the limits for any model. Constraints are also placed on models predicting doubly charged Higgs bosons and excited leptons. For doubly charged Higgs bosons decaying to $e\tau$ or $\mu\tau$, lower limits on the mass are set at 400 GeV at 95% confidence level. For excited leptons, constraints are provided as functions of both the mass of the excited state and the compositeness scale $\Lambda$, with the strongest mass constraints arising in regions where the mass equals $\Lambda$. In such scenarios, lower mass limits are set at 2.0 TeV for excited electrons and muons, 1.8 TeV for excited taus, and 1.6 TeV for every excited-neutrino flavour. UPDATE (18 MAY 2015): Updated fiducial lepton efficiencies.

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Data from Table 4

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Expected and observed event yields for the most inclusive signal regions.

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Data from Table 5

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Expected and observed limits on $\sigma_{95}^{\mathrm{vis}}$ for inclusive signal regions, along with confidence intervals of one and two standard deviations...

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Data from Table 6

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The fiducial efficiency for electrons, muons, and taus in different $p_{\mathrm{T}}$ ranges ($\epsilon_{\mathrm{fid}}(p_{\mathrm{T}})$). For electrons and muons from tau decays,...

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Data from Table 7

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The fiducial efficiency for electrons and taus in different $\eta$ ranges ($\epsilon_{\mathrm{fid}}(\eta)$). For electrons from tau decays, the $\eta$ is...

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Data from Table 10

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Expected and observed event yields for the $H_{\mathrm{T}}^{\mathrm{leptons}}$ signal regions.

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Data from Table 11

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Expected and observed event yields for the minimum $p_{\mathrm{T}}^{\ell}$ signal regions.

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Data from Table 12

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Expected and observed event yields for the $b$-tag signal regions.

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Data from Table 13

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Expected and observed event yields for the inclusive $m_{\mathrm{eff}}$ signal regions.

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Data from Table 14

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Expected and observed event yields for the high-$E_{\mathrm{T}}^{\mathrm{miss}}$, $m_{\mathrm{eff}}$ signal regions.

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Data from Table 15

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Expected and observed event yields for the high-$m_{\mathrm{T}}^{W}$, $m_{\mathrm{eff}}$ signal regions.

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Data from Table 16

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Expected and observed event yields for the high-$H_{\mathrm{T}}^{\mathrm{jets}}$, $E_{\mathrm{T}}^{\mathrm{miss}}$ signal regions.

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Data from Table 17

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Expected and observed event yields for the low-$H_{\mathrm{T}}^{\mathrm{jets}}$, $E_{\mathrm{T}}^{\mathrm{miss}}$ signal regions.

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Data from Table 18

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $H_{\mathrm{T}}^{\mathrm{leptons}}$.

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Data from Table 19

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $p_{\mathrm{T}}^{\ell\mathrm{,min}}$.

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Data from Table 20

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on the...

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Data from Table 21

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $m_{\mathrm{eff}}$.

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Data from Table 22

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $m_{\mathrm{eff}}$...

• #### Table 18

Data from Table 23

10.17182/hepdata.66248.v1/t18

Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $m_{\mathrm{eff}}$...

• #### Table 19

Data from Table 24

10.17182/hepdata.66248.v1/t19

Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $E_{\mathrm{T}}^{\mathrm{miss}}$....

• #### Table 20

Data from Table 25

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Expected and observed limits, and corresponding $p$-values and significances (in standard deviations), for signal regions based on cuts on $E_{\mathrm{T}}^{\mathrm{miss}}$....