Limits...
Search for dark matter in events with heavy quarks and missing transverse momentum in [Formula: see text] collisions with the ATLAS detector.

- Eur Phys J C Part Fields (2015)

Bottom Line: The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles.These limits are particularly strong for low-mass dark matter.Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter.

View Article: PubMed Central - PubMed

Affiliation: CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.

ABSTRACT

This article reports on a search for dark matter pair production in association with bottom or top quarks in [Formula: see text] of [Formula: see text] collisions collected at [Formula: see text] TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing [Formula: see text]-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter.

No MeSH data available.


Upper limits at 90 % CL on the spin-dependent –nucleon cross-section () for the tensor operator D9 (red) as a function of . The yellow and green curves represent the exclusion limits recently set by the COUPP and PICASSO collaborations [8, 9, 65]. The coupling is assumed to be
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Fig6: Upper limits at 90 % CL on the spin-dependent –nucleon cross-section () for the tensor operator D9 (red) as a function of . The yellow and green curves represent the exclusion limits recently set by the COUPP and PICASSO collaborations [8, 9, 65]. The coupling is assumed to be

Mentions: Figure 4 shows the 90 % CL exclusion curves for the effective mass scale as a function of . The results for the operators D1, C1, and D9 are presented individually for all four signal regions. The best limits on the D1 and C1 operators are obtained using SR4, while SR1 provides the best limits on the D9 operator, as shown in Fig. 4. These limits are then converted into limits on the –nucleon cross-section [12]. Figures 5 and 6 show the corresponding 90 % CL exclusion curves for the spin-independent and spin-dependent –nucleon cross-section for the scalar (D1) and tensor (D9) operators as a function of for the strongest results obtained in any signal region. The most stringent limits set by direct detection experiments [6–9] are also shown. Only where more then of the events fulfill the effective field theory validity constraints are shown in Figs. 5 and 6.


Search for dark matter in events with heavy quarks and missing transverse momentum in [Formula: see text] collisions with the ATLAS detector.

- Eur Phys J C Part Fields (2015)

Upper limits at 90 % CL on the spin-dependent –nucleon cross-section () for the tensor operator D9 (red) as a function of . The yellow and green curves represent the exclusion limits recently set by the COUPP and PICASSO collaborations [8, 9, 65]. The coupling is assumed to be
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4376411&req=5

Fig6: Upper limits at 90 % CL on the spin-dependent –nucleon cross-section () for the tensor operator D9 (red) as a function of . The yellow and green curves represent the exclusion limits recently set by the COUPP and PICASSO collaborations [8, 9, 65]. The coupling is assumed to be
Mentions: Figure 4 shows the 90 % CL exclusion curves for the effective mass scale as a function of . The results for the operators D1, C1, and D9 are presented individually for all four signal regions. The best limits on the D1 and C1 operators are obtained using SR4, while SR1 provides the best limits on the D9 operator, as shown in Fig. 4. These limits are then converted into limits on the –nucleon cross-section [12]. Figures 5 and 6 show the corresponding 90 % CL exclusion curves for the spin-independent and spin-dependent –nucleon cross-section for the scalar (D1) and tensor (D9) operators as a function of for the strongest results obtained in any signal region. The most stringent limits set by direct detection experiments [6–9] are also shown. Only where more then of the events fulfill the effective field theory validity constraints are shown in Figs. 5 and 6.

Bottom Line: The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles.These limits are particularly strong for low-mass dark matter.Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter.

View Article: PubMed Central - PubMed

Affiliation: CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.

ABSTRACT

This article reports on a search for dark matter pair production in association with bottom or top quarks in [Formula: see text] of [Formula: see text] collisions collected at [Formula: see text] TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing [Formula: see text]-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter.

No MeSH data available.