Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3 fb$^{-1}$ of integrated luminosity at $\sqrt{s}$=8 TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet-mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the Standard Model expectations, and limits are set on the mass scale in effective field theories that describe the interaction of dark matter and Standard Model particles.
16 September 2013
Contact: Exotics conveners
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Figures
Figure 01a
Pair production of WIMPs (χχ) in proton--proton collisions at the LHC via an unknown intermediate state, with initial-state radiation of a W boson.
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Figure 01b
Pair production of WIMPs (χχ) in proton--proton collisions at the LHC via an unknown intermediate state, with initial-state radiation of a W boson.
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Figure 02
Distribution of mjet in the data and for the predicted background in the top control region (CR) with one muon, one large-radius jet, two narrow jets, at least one b-tag, and ETmiss >250 GeV, which includes a W peak and a tail due to inclusion of (part of) the b jet from top decay. Uncertainties include statistical and systematic sources.
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Figure 03
Distribution of mjet in the data and for the predicted background in the signal regions (SR) with ETmiss > 350 GeV (top) and ETmiss > 500 GeV (bottom). Also shown are the combined mono-W-boson and mono-Z-boson signal distributions with mχ=1 GeV and M*=1 TeV for the D5 destructive and D5 constructive cases, scaled by factors defined in the legends. Uncertainties include statistical and systematic contributions.
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Figure 04
Observed limits on the effective theory mass scale M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for various operators. For each operator, the values below the corresponding line are excluded.
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Figure 05
Limits on χ--nucleon cross sections as a function of mχ at 90% CL for spin-independent (left) and spin-dependent (right) cases, compared to previous limits.
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Figure 06
Limit on the Higgs boson cross section for decay to invisible particles divided by the cross section for decays to Standard Model particles as a function of mH at 95% CL, derived from the signal region (SR) with ETmiss > 350 GeV.
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Auxiliary material
Figure 01
Distribution of mjet in the data and for the predicted background in the μ control region (CR) with one muon, one large-radius jet, and ETmiss > 350 GeV. Uncertainties include statistical and systematic sources.
png (73kB) pdf (13kB)
Figure 02a
Distribution of mjet in the data and for the predicted background in Z control region (CR) with ETmiss > 350 GeV (top) and low ETmiss CR with ETmiss in [250,350] GeV (bottom).
png (63kB) pdf (13kB)
Figure 02b
Distribution of mjet in the data and for the predicted background in Z control region (CR) with ETmiss > 350 GeV (top) and low ETmiss CR with ETmiss in [250,350] GeV (bottom).
png (64kB) pdf (13kB)
Figure 03a
Distribution of mjet in the data and for the predicted background in the signal regions (SR) with ETmiss > 350 GeV (top) and ETmiss >500 GeV (bottom). Also shown are the combined mono-W-boson and mono-Z-boson signal distributions with mχ=1 GeV and M*=1 TeV for the D5 destructive and D5 constructive cases, scaled by factors defined in the legends. Uncertainties include statistical and systematic contributions.
png (71kB) pdf (13kB)
Figure 03b
Distribution of mjet in the data and for the predicted background in the signal regions (SR) with ETmiss > 350 GeV (top) and ETmiss >500 GeV (bottom). Also shown are the combined mono-W-boson and mono-Z-boson signal distributions with mχ=1 GeV and M*=1 TeV for the D5 destructive and D5 constructive cases, scaled by factors defined in the legends. Uncertainties include statistical and systematic contributions.
png (87kB) pdf (13kB)
Figure 04
Fraction of W bosons as a function of mχ in combined mono-W-boson and mono-Z-boson signal samples for various operators.
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Figure 05a
Limits on σ × A × ε as a function of W boson fraction from combined mono-W-boson and mono-Z-boson signal samples in the signal regions (SR) with ETmiss > 350 GeV (top) and ETmiss > 500 GeV (bottom), derived from taking W and Z boson peaks in D5 destructive operator with mχ=1 GeV.
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Figure 05b
Limits on σ × A × ε as a function of W boson fraction from combined mono-W-boson and mono-Z-boson signal samples in the signal regions (SR) with ETmiss > 350 GeV (top) and ETmiss > 500 GeV (bottom), derived from taking W and Z boson peaks in D5 destructive operator with mχ=1 GeV.
png (47kB) pdf (12kB)
Figure 06a
Limits on M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for D9 operator in the signal region (SR) with ETmiss > 500 GeV (top), D5 constructive operator in the SR with ETmiss > 500 GeV (middle), and D5 destructive operator in the SR with ETmiss > 350 GeV (bottom).
png (64kB) pdf (12kB)
Figure 06b
Limits on M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for D9 operator in the signal region (SR) with ETmiss > 500 GeV (top), D5 constructive operator in the SR with ETmiss > 500 GeV (middle), and D5 destructive operator in the SR with ETmiss > 350 GeV (bottom).
png (62kB) pdf (12kB)
Figure 06c
Limits on M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for D9 operator in the signal region (SR) with ETmiss > 500 GeV (top), D5 constructive operator in the SR with ETmiss > 500 GeV (middle), and D5 destructive operator in the SR with ETmiss > 350 GeV (bottom).
png (63kB) pdf (12kB)
Figure 07a
Limits on M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for D1 operator in with signal region (SR) with ETmiss > 500 GeV (top) and C1 operator in the SR with ETmiss > 500 GeV (bottom).
png (57kB) pdf (11kB)
Figure 07b
Limits on M* as a function of mχ at 90% CL from combined mono-W-boson and mono-Z-boson signals for D1 operator in with signal region (SR) with ETmiss > 500 GeV (top) and C1 operator in the SR with ETmiss > 500 GeV (bottom).
png (60kB) pdf (11kB)
Figure 08a
Limits on χ--nucleon cross sections as a function of mχ at 90% CL for spin-independent (left) and spin-dependent (right) cases, compared to previous limits.
png (78kB) pdf (14kB)
Figure 08b
Limits on χ--nucleon cross sections as a function of mχ at 90% CL for spin-independent (left) and spin-dependent (right) cases, compared to previous limits.
png (72kB) pdf (12kB)
