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Open AccessJournal ArticleDOI

Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at √s=13TeV

Albert M. Sirunyan, +2174 more
- 08 Jun 2017 - 
- Vol. 77, Iss: 12, pp 845-845
TLDR
This analysis is the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states and provides exclusions that are stronger than those achieved with individual heavy- Flavour final states.
Abstract
A search is presented for an excess of events with heavy-flavor quark pairs ( ${t}\overline{{t}} $ and ${b} \overline{{b}} $ ) and a large imbalance in transverse momentum in data from proton–proton collisions at a center-of-mass energy of 13 $\,\text{TeV}$ . The data correspond to an integrated luminosity of 2.2 $\,\text{fb}^{-1}$ collected with the CMS detector at the CERN LHC. No deviations are observed with respect to standard model predictions. The results are used in the first interpretation of dark matter production in ${t}\overline{{t}} $ and ${b} \overline{{b}} $ final states in a simplified model. This analysis is also the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states. The combination provides exclusions that are stronger than those achieved with individual heavy-flavor final states.

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Journal ArticleDOI

GeV-scale thermal WIMPs: Not even slightly ruled out

Abstract: Weakly interacting massive particles (WIMPs) have long reigned as one of the leading classes of dark matter candidates. The observed dark matter abundance can be naturally obtained by freezeout of weak-scale dark matter annihilations in the early Universe. This ``thermal WIMP'' scenario makes direct predictions for the total annihilation cross section that can be tested in present-day experiments. While the dark matter mass constraint can be as high as ${m}_{\ensuremath{\chi}}\ensuremath{\gtrsim}100\text{ }\text{ }\mathrm{GeV}$ for particular annihilation channels, the constraint on the total cross section has not been determined. We construct the first model-independent limit on the WIMP total annihilation cross section, showing that allowed combinations of the annihilation-channel branching ratios considerably weaken the sensitivity. For thermal WIMPs with $s$-wave $2\ensuremath{\rightarrow}2$ annihilation to visible final states, we find the dark matter mass is only known to be ${m}_{\ensuremath{\chi}}\ensuremath{\gtrsim}20\text{ }\text{ }\mathrm{GeV}$. This is the strongest largely model-independent lower limit on the mass of thermal-relic WIMPs; together with the upper limit on the mass from the unitarity bound (${m}_{\ensuremath{\chi}}\ensuremath{\lesssim}100\text{ }\text{ }\mathrm{TeV}$), it defines what we call the ``WIMP window.'' To probe the remaining mass range, we outline ways forward.
Journal ArticleDOI

Search for top-squark pair production in final states with one lepton, jets, and missing transverse momentum using 36 fb−1 of s√=13 TeV pp collision data with the ATLAS detector

Morad Aaboud, +2952 more
TL;DR: In this article, the results of a search for the direct pair production of top quarks, the supersymmetric partner of the top quark, in final states with one isolated electron or muon, several energetic jets, and missing transverse momentum are reported.
Journal ArticleDOI

Search for dark matter produced in association with bottom or top quarks in s=13 TeV pp collisions with the ATLAS detector.

Morad Aaboud, +2886 more
TL;DR: A search for weakly interacting massive dark-matter particles produced in association with bottom or top quarks is presented and limits on the production cross-section of 300 times the predicted rate for mediators with masses between 10 and 50GeV are set.
Journal ArticleDOI

Search for top squarks and dark matter particles in opposite-charge dilepton final states at s = 13 TeV

Albert M. Sirunyan, +2230 more
- 01 Feb 2018 - 
TL;DR: In this article, a search for new physics in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from b quarks, and missing transverse momentum (pTmiss) was presented.
Journal ArticleDOI

Constraints on mediator-based dark matter and scalar dark energy models using s√ = 13 TeV pp collision data collected by the ATLAS detector

Morad Aaboud, +2958 more
TL;DR: In this paper, the authors propose a scalar dark energy model using up to 37 fb(-1) = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016.
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