scholarly journals Search for production of four top quarks in final states with same-sign or multiple leptons in proton–proton collisions at $$\sqrt{s}=13$$ $$\,\text {TeV}$$

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Top Quark ◽  
Center Of Mass ◽  
Top Quarks ◽  
Higgs Doublet ◽  
Effective Field ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Abstract The standard model (SM) production of four top quarks ($$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$tt¯tt¯) in proton–proton collisions is studied by the CMS Collaboration. The data sample, collected during the 2016–2018 data taking of the LHC, corresponds to an integrated luminosity of 137$$\,\text {fb}^{-1}$$fb-1 at a center-of-mass energy of 13$$\,\text {TeV}$$TeV. The events are required to contain two same-sign charged leptons (electrons or muons) or at least three leptons, and jets. The observed and expected significances for the $$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$tt¯tt¯ signal are respectively 2.6 and 2.7 standard deviations, and the $$\text {t} {}{\overline{\text {t}}} \text {t} {}{\overline{\text {t}}} $$tt¯tt¯ cross section is measured to be $$12.6^{+5.8}_{-5.2}\,\text {fb} $$12.6-5.2+5.8fb. The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, $$y_{\text {t}}$$yt, yielding a limit of $$|y_{\text {t}}/y_{\text {t}}^{\mathrm {SM}} | < 1.7$$|yt/ytSM|<1.7 at $$95\%$$95% confidence level, where $$y_{\text {t}}^{\mathrm {SM}}$$ytSM is the SM value of $$y_{\text {t}}$$yt. They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, $$\hat{H}<0.12$$H^<0.12. Limits are set on the production of a heavy scalar or pseudoscalar boson in Type-II two-Higgs-doublet and simplified dark matter models, with exclusion limits reaching 350–470$$\,\text {GeV}$$GeV and 350–550$$\,\text {GeV}$$GeV for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles.

scholarly journals Search for new physics in top quark production with additional leptons in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV using effective field theory

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Top Quark ◽  
Center Of Mass ◽  
Top Quarks ◽  
New Physics ◽  
Effective Field ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

Abstract Events containing one or more top quarks produced with additional prompt leptons are used to search for new physics within the framework of an effective field theory (EFT). The data correspond to an integrated luminosity of 41.5 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, collected by the CMS experiment in 2017. The selected events are required to have either two leptons with the same charge or more than two leptons; jets, including identified bottom quark jets, are also required, and the selected events are divided into categories based on the multiplicities of these objects. Sixteen dimension-six operators that can affect processes involving top quarks produced with additional charged leptons are considered in this analysis. Constructed to target EFT effects directly, the analysis applies a novel approach in which the observed yields are parameterized in terms of the Wilson coefficients (WCs) of the EFT operators. A simultaneous fit of the 16 WCs to the data is performed and two standard deviation confidence intervals for the WCs are extracted; the standard model expectations for the WC values are within these intervals for all of the WCs probed.

Implementation of the CMS-HIG-18-011 analysis in the MadAnalysis 5 framework (exotic Higgs decays via two pseudoscalars with two muons and two b-jets; 35.9 fb−1)

2020 ◽  
pp. 2141003
Author(s):  
Joon-Bin Lee ◽  
Jehyun Lee
Keyword(s):  
Higgs Boson ◽  
Center Of Mass ◽  
Final State ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Cms Experiment ◽  
The Standard Model ◽  
Proton Proton Collisions ◽  
Selection Of

We present the implementation in the MadAnalysis 5 framework of the CMS-HIG-18-011 search for exotic decays of the Standard Model Higgs boson, in which the Higgs boson is assumed to decay into a pair of light pseudoscalar [Formula: see text], that then further decay into a di-muon and di-[Formula: see text]-jet final state. This analysis considers proton-proton collisions at a center-of-mass energy of 13 TeV and data collected by the CMS experiment in 2016, with an integrated luminosity of 35.9 fb[Formula: see text]. We present a selection of recast predictions, obtained with MadAnalysis 5 and Delphes 3, that include a few differential distributions, yields, and efficiencies. We show that they agree at a level of a few percent with public CMS results.

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 Search for chargino-neutralino production in events with Higgs and W bosons using 137 fb−1 of proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
W Boson ◽  
Center Of Mass ◽  
W Bosons ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Missing Transverse Momentum ◽  
The Masses ◽  
Proton Proton Collisions

Abstract A search for electroweak production of supersymmetric (SUSY) particles in final states with one lepton, a Higgs boson decaying to a pair of bottom quarks, and large missing transverse momentum is presented. The search uses data from proton-proton collisions at a center-of-mass energy of 13 TeV collected using the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb−1. The observed yields are consistent with backgrounds expected from the standard model. The results are interpreted in the context of a simplified SUSY model of chargino-neutralino production, with the chargino decaying to a W boson and the lightest SUSY particle (LSP) and the neutralino decaying to a Higgs boson and the LSP. Charginos and neutralinos with masses up to 820 GeV are excluded at 95% confidence level when the LSP mass is small, and LSPs with mass up to 350 GeV are excluded when the masses of the chargino and neutralino are approximately 700 GeV.

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 Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV

2012 ◽  
Vol 2012 (10) ◽  
Author(s):  
Benjamin Fuks ◽  
Michael Klasen ◽  
David R. Lamprea ◽  
Marcel Rothering
Keyword(s):  
Center Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
8 Tev ◽  
Proton Proton Collisions
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