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.

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.

Search for physics beyond the Standard Model using jet observables

2015 ◽  
Vol 30 (31) ◽  
pp. 1546009 ◽  
Author(s):  
Konstantinos Kousouris
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final States ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
The Standard Model ◽  
8 Tev ◽  
Jet Observables

Jet observables have been exploited extensively during the LHC Run 1 to search for physics beyond the Standard Model. In this article, the most recent results from the ATLAS and CMS collaborations are summarized. Data from proton–proton collisions at 7 and 8 TeV center-of-mass energy have been analyzed to study monojet, dijet, and multijet final states, searching for a variety of new physics signals that include colored resonances, contact interactions, extra dimensions, and supersymmetric particles. The exhaustive searches with jets in Run 1 did not reveal any signal, and the results were used to put stringent exclusion limits on the new physics models.

Production of a light top-squark pair in association with a light non-SM Higgs boson within the NMSSM from proton–proton collisions at s = 13 TeV and 33 TeV

2019 ◽  
Vol 34 (22) ◽  
pp. 1950125
Author(s):  
Siba P. Das ◽  
Jorge F. Fraga ◽  
Carlos Avila
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Center Of Mass ◽  
Top Squark ◽  
Proton Proton ◽  
Proton Collisions ◽  
Physical Constraints ◽  
Leptonic Decays ◽  
Proton Proton Collisions

We study the production of a light top-squark pair in association with the lightest Higgs boson [Formula: see text], as predicted by the Next-to-Minimal Supersymmetric Standard Model (NMSSM) in proton–proton collisions at center-of-mass energies of 13 TeV and 33 TeV. We scan randomly about 10 million points of the NMSSM parameter space, allowing all possible decays of the lightest top-squark and lightest Higgs boson, with no further assumptions, except for known physical constraints such as perturbative bounds, dark matter relic density consistent with recent Planck experiment measurements, Higgs mass bounds on the next to lightest Higgs boson, [Formula: see text], assuming it is consistent with LHC measurements for the Standard Model Higgs boson, LEP bounds for the chargino mass and [Formula: see text] invisible width, experimental bounds on [Formula: see text] meson rare decays and some LHC experimental bounds on SUSY particle spectra different to the particles involved in our analysis. We find that for low mass top-squark, the dominating decay mode is [Formula: see text] with [Formula: see text]. We use three benchmark points with the highest cross-sections, which naturally fall within the compressed spectra of the top-squark, and make a phenomenological analysis to determine the optimal event selection that maximizes the signal significance over backgrounds. We focus on the leptonic decays of both [Formula: see text]’s and the decay of the lightest Higgs boson into [Formula: see text]-quarks [Formula: see text]. Our results show that the high luminosity LHC will have limitations to observe the studied SUSY scenario and only a proton collider with a collision energy above 33 TeV will be able to observe this signal with more than three standard deviations over background, albeit for stop masses below 300 GeV.

scholarly journals Measurement of prompt open-charm production cross sections in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Theoretical Calculations ◽  
Production Cross ◽  
Center Of Mass ◽  
Open Charm ◽  
Charm Mesons ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Abstract The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13 TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb−1. The differential production cross sections of the D∗±, D±, and D0$$ \left({\overline{\mathrm{D}}}^0\right) $$ D ¯ 0 mesons are presented in ranges of transverse momentum and pseudorapidity 4 < pT< 100 GeV and |η| < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.

scholarly journals Measurement of the Z boson differential production cross section using its invisible decay mode (Z → $$ \nu \overline{\nu} $$) in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Cross Sections ◽  
Z Boson ◽  
Production Cross ◽  
Center Of Mass ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Abstract Measurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were collected by the CMS detector in 2016 and correspond to an integrated luminosity of 35.9 fb−1. In these measurements, events are selected containing an imbalance in transverse momentum and one or more energetic jets. The fiducial differential cross section is measured as a function of the Z boson transverse momentum. The results are combined with a previous measurement of charged-lepton decays of the Z boson. The measured total fiducial cross section for events with Z boson transverse momentum greater than 200 GeV is $$ {3000}_{-170}^{+180} $$ 3000 − 170 + 180 fb.

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-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.

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