scholarly journals Collider Searches for Dark Matter (ATLAS + CMS)

Universe ◽  
2018 ◽  
Vol 4 (11) ◽  
pp. 131 ◽  
Author(s):  
Nicolò Trevisani
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Direct Detection ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Interaction Cross Section ◽  
Proton Proton ◽  
Mass Distributions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Several searches for dark matter have been performed by the CMS and ATLAS collaborations, using proton-proton collisions with a center-of-mass energy of 13 TeV produced by the Large Hadron Collider. Different signatures may highlight the presence of dark matter: the imbalance in the transverse momentum in an event due to the presence of undetectable dark matter particles, produced together with one Standard Model particle, a bump in the di-jet or di-lepton invariant mass distributions, or an excess of events in the di-jet angular distribution, produced by a dark matter mediator. No significant discrepancies with respect to the Standard Model predictions have been found in data, so that limits on the dark matter couplings to ordinary matter, or limits on the dark matter particles and mediators masses have been set. The results are also re-interpreted as limits on the dark matter interaction cross-section with baryonic matter, so that a comparison with direct detection experiments is allowed.

Implementation of the CMS-EXO-17-015 analysis in the MadAnalysis 5 framework (leptoquark and dark matter with one muon, one jet and missing transverse energy; 77.4 fb−1)

2020 ◽  
pp. 2141002
Author(s):  
Benjamin Fuks ◽  
Adil Jueid
Keyword(s):  
Dark Matter ◽  
Transverse Energy ◽  
Center Of Mass ◽  
Missing Transverse Energy ◽  
Final State ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Scalar Leptoquarks ◽  
Proton Proton Collisions

We present an implementation of the CMS-EXO-17-015 analysis in the MadAnalysis 5 framework. The analysis targets a search for dark matter in a channel in which it originates from the production and decay of a pair of scalar leptoquarks. This search considers a luminosity [Formula: see text] of CMS data collected in 2016 and 2017, in proton-proton collisions at a center-of-mass energy of 13 TeV. The final state signature is comprised of one isolated highly-energetic muon, one jet with a large transverse momentum and a significant amount of missing transverse energy. We validate our implementation in MadAnalysis 5 for a specific leptoquark/dark matter benchmark scenario. In particular, we compare predictions obtained with MadAnalysis 5 with the official CMS results for various kinematical distributions relevant for the CMS-EXO-17-015 analysis, as well as detailed cut-flow tables. We have found an excellent agreement.

scholarly journals Search for physics beyond the standard model in events with jets and two same-sign or at least three charged leptons in proton-proton collisions at $$\sqrt{s}=13\,{\text {TeV}} $$

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Center Of Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Charged Leptons ◽  
Proton Proton Collisions

Abstract A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of $$137{\,{\text {fb}}^{-1}} $$137fb-1 at a center-of-mass energy of $$13\,{\text {TeV}} $$13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as $$2.1\,{\text {TeV}} $$2.1TeV for gluinos and $$0.9\,{\text {TeV}} $$0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.

scholarly journals SEARCHES FOR SUPERSYMMETRY WITH THE ATLAS DETECTOR

2012 ◽  
Vol 27 (32) ◽  
pp. 1230033 ◽  
Author(s):  
G. REDLINGER
Keyword(s):  
Large Hadron Collider ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Atlas Detector ◽  
Mass Energy ◽  
Future Directions ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

This is a review of searches for supersymmetry (SUSY) with the ATLAS detector in proton–proton collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider (LHC) at CERN. The review covers results that have been published, or submitted for publication, up to September 2012, many of which cover the full 7 TeV data-taking period. No evidence for SUSY has been seen; some possibilities for future directions are discussed.

Implementation of the CMS-TOP-18-003 analysis in the MadAnalysis 5 framework (four top quarks with at least two leptons; 137 fb−1)

2020 ◽  
pp. 2141008
Author(s):  
Luc Darmé ◽  
Benjamin Fuks
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
Top Quarks ◽  
New Physics ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
The Standard Model ◽  
Physics Model ◽  
Proton Proton Collisions

We present the implementation in MadAnalysis 5 of the CMS-TOP-18-003 search for the production of four top quarks in the Standard Model and detail the validation of this implementation. This CMS analysis studies Standard Model four-top production through the same-sign and multi-lepton plus jets channels, using a luminosity of 137 fb[Formula: see text] of proton-proton collisions at a center-of-mass energy of 13 TeV. We validate our implementation work by studying various distributions and event counts describing the properties of the signal in the context of the Standard Model: jet and [Formula: see text]-jet multiplicities, the hadronic activity [Formula: see text], and the number of expected events populating the various analysis signal regions. We then provide a small example of usage of this implementation to constrain a toy new physics model.

scholarly journals Searching for dark matter at hadron colliders

2014 ◽  
Vol 29 (23) ◽  
pp. 1430041 ◽  
Author(s):  
Andrew Askew ◽  
Sushil Chauhan ◽  
Björn Penning ◽  
William Shepherd ◽  
Mani Tripathi
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Hadron Collider ◽  
Effective Field ◽  
Current Status ◽  
Hadron Colliders ◽  
Proton Proton ◽  
Proton Collisions ◽  
8 Tev ◽  
Proton Proton Collisions

Theoretical and experimental techniques employed in dedicated searches for dark matter at hadron colliders are reviewed. Bounds from the 7 TeV and 8 TeV proton–proton collisions at the Large Hadron Collider (LHC) on dark matter interactions have been collected and the results interpreted. We review the current status of the Effective Field Theory picture of dark matter interactions with the Standard Model. Currently, LHC experiments have stronger bounds on operators leading to spin-dependent scattering than direct detection experiments, while direct detection probes are more constraining for spin-independent scattering for WIMP masses above a few GeV.

scholarly journals Measurement of the Higgs Boson Mass in the H → ZZ∗→ 4ℓ and H → γγ Channels with s = 13TeV pp Collisions Using the ATLAS Detector

2018 ◽  
Vol 46 ◽  
pp. 1860052
Author(s):  
N. Bruscino
Keyword(s):  
Higgs Boson ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Atlas Detector ◽  
Boson Mass ◽  
Proton Collision ◽  
Proton Proton ◽  
Decay Channels ◽  
Mass Distributions ◽  
Center Of Mass Energy

The mass of the Higgs boson is measured in the [Formula: see text] and in the [Formula: see text] decay channels with [Formula: see text]fb[Formula: see text] of proton-proton collision data from the Large Hadron Collider at a center-of-mass energy of [Formula: see text] TeV recorded by the ATLAS detector in 2015 and 2016. The measured value in the [Formula: see text] channel is [Formula: see text]GeV, while the measured value in the [Formula: see text] channel is [Formula: see text]GeV. The two results have a compatibility of [Formula: see text]. The combined measurement from a simultaneous fit to the invariant mass distributions in the two channels is [Formula: see text]GeV.

scholarly journals The CMS ECAL Upgrade for Precision Crystal Calorimetry at the HL-LHC

2018 ◽  
Vol 46 ◽  
pp. 1860074
Author(s):  
D. A. Petyt
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Electromagnetic Calorimeter ◽  
Mass Energy ◽  
Test Beam ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Present Test ◽  
Proton Proton Collisions

The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid Experiment (CMS) is operating at the Large Hadron Collider (LHC) with proton-proton collisions at 13 TeV center-of-mass energy and at a bunch spacing of 25 ns. Upgrades are necessary for the High-Luminosity upgrade of the LHC (HL-LHC). We review the design and R&D studies for the CMS ECAL crystal calorimeter upgrade. We present test beam results of hadron irradiated PbWO4 crystals up to fluences expected at the HL-LHC. We also report on the R&D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

scholarly journals Diboson production in proton–proton collisions at $\sqrt{s} = 7~{\rm TeV}$

2014 ◽  
Vol 29 (26) ◽  
pp. 1430053 ◽  
Author(s):  
Matthias Schott ◽  
Junjie Zhu
Keyword(s):  
Production Cross ◽  
Hadron Collider ◽  
Center Of Mass ◽  
General Purpose ◽  
Proton Proton ◽  
Diboson Production ◽  
Center Of Mass Energy ◽  
New Energy ◽  
Electroweak Boson ◽  
Proton Proton Collisions

This review summarizes results on the production cross-section measurements of electroweak boson pairs (WW, WZ, ZZ, Wγ and Zγ) at the Large Hadron Collider (LHC) in pp collisions at a center-of-mass energy of [Formula: see text]. The two general-purpose detectors at the LHC, ATLAS and CMS recorded an integrated luminosity of ≈5 fb -1 in 2011, which offered the possibility to study the properties of diboson production to high precision. These measurements test predictions of the Standard Model (SM) in a new energy regime and are crucial for the understanding and the measurement of the SM Higgs boson and other new particles. In this review, special emphasis is drawn on the combination of results from both experiments and a common interpretation with respect to state-of-the-art SM predictions.

scholarly journals Future prospects for the minimal supersymmetric standard model

2021 ◽  
pp. 2150188
Author(s):  
Shehu AbdusSalam ◽  
Safura S. Barzani ◽  
Mohammadreza Noormandipour
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Cold Dark Matter ◽  
Direct Detection ◽  
Hadron Collider ◽  
Hadron Colliders ◽  
Future Prospects ◽  
Lower Limits

Experimental collaborations for the large hadron collider conducted various searches for supersymmetry. In the absence of signals, lower limits were put on sparticle masses but usually within frameworks with (over-)simplifications relative to the entire indications by supersymmetry models. For complementing current interpretations of experimental bounds, we introduce a 30-parameter version of the R-parity conserving Minimal Supersymmetric Standard Model (MSSM-30). Using a sample of the MSSM-30 which are in harmony with cold dark matter, flavor and precision electroweak constraints, we explicitly show the prospects for assessing neutralino candidate dark matter in contrast to future searches for supersymmetry. The MSSM-30-parameter regions that are beyond reach to dark matter direct detection experiments could be probed by future hadron–hadron colliders.

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