TeV In Final States Research Articles

Observation of triple J/ψ meson production in proton-proton collisions at √ s = 13 TeV

The first observation of the three J/ψ meson production in proton-proton collisions at a center-of-mass energy of 13 TeV in final states with three µ +µ − pairs is reported. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 133 fb−1 . The pp → J/ψ J/ψ J/ψ X process is observed with a significance in excess of five standard deviations. The fiducial cross section for this process is found to be σ(pp → J/ψ J/ψ J/ψ X) = 272+141 −104(stat)±17(syst) fb. The result is compared to theoretical expectations for the production of three J/ψ mesons in single (SPS), double- (DPS), and triple- (TPS) parton scattering processes. Under the most economical assumption of factorization of multiple hard scattering probabilities in terms of SPS cross sections, the measured final state is found to be dominated by DPS and TPS contributions. A value of the associated DPS effective cross section parameter of σeff,DPS = 2.7 +1.4 −1.0 (exp)+1.5 −1.0 (theo) mb, related to the transverse distribution of partons in the proton, is derived.

Implementation of the CMS-SUS-19-006 analysis in the MadAnalysis 5 framework (supersymmetry with large hadronic activity and missing transverse energy; 137 fb−1)

We present the MadAnalysis 5 implementation and validation of the analysis Search for supersymmetry in proton-proton collisions at 13 TeV in final states with jets and missing transverse momentum (CMS-SUS-19-006). The search targets signatures with at least two jets and large missing transverse momentum in the all-hadronic final state. The analyzed luminosity is 137 fb[Formula: see text], corresponding to the Run 2 proton-proton data set recorded by the CMS detector at 13 TeV. This implementation has been validated in a variety of simplified models, by comparing derived cut flow tables and histograms with information provided by the CMS collaboration, using event samples that we simulated for the purpose of this re-implementation study. The validation is found to reproduce the signal acceptance in most cases.

Search for supersymmetry in proton-proton collisions at 13 TeV in final states with jets and missing transverse momentum

Results are reported from a search for supersymmetric particles in the final state with multiple jets and large missing transverse momentum. The search uses a sample of proton-proton collisions at sqrt{s} = 13 TeV collected with the CMS detector in 2016–2018, corresponding to an integrated luminosity of 137 fb−1, representing essentially the full LHC Run 2 data sample. The analysis is performed in a four-dimensional search region defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No significant excess in the event yield is observed relative to the expected background contributions from standard model processes. Limits on the pair production of gluinos and squarks are obtained in the framework of simplified models for supersymmetric particle production and decay processes. Assuming the lightest supersymmetric particle to be a neutralino, lower limits on the gluino mass as large as 2000 to 2310 GeV are obtained at 95% confidence level, while lower limits on the squark mass as large as 1190 to 1630 GeV are obtained, depending on the production scenario.

Search for natural and split supersymmetry in proton-proton collisions at sqrt{s}=13 TeV in final states with jets and missing transverse momentum

A search for supersymmetry (SUSY) is performed in final states comprising one or more jets and missing transverse momentum using data from proton-proton collisions at a centre-of-mass energy of 13 TeV. The data were recorded with the CMS detector at the CERN LHC in 2016 and correspond to an integrated luminosity of 35.9 fb−1. The number of signal events is found to agree with the expected background yields from standard model processes. The results are interpreted in the context of simplified models of SUSY that assume the production of gluino or squark pairs and their prompt decay to quarks and the lightest neutralino. The masses of bottom, top, and mass-degenerate light-flavour squarks are probed up to 1050, 1000, and 1325 GeV, respectively. The gluino mass is probed up to 1900, 1650, and 1650 GeV when the gluino decays via virtual states of the aforementioned squarks. The strongest mass bounds on the neutralinos from gluino and squark decays are 1150 and 575 GeV, respectively. The search also provides sensitivity to simplified models inspired by split SUSY that involve the production and decay of long-lived gluinos. Values of the proper decay length cτ0 from 10−3 to 105 mm are considered, as well as a metastable gluino scenario. Gluino masses up to 1750 and 900 GeV are probed for cτ0 = 1 mm and for the metastable state, respectively. The sensitivity is moderately dependent on model assumptions for cτ0 ≳ 1 m. The search provides coverage of the cτ0 parameter space for models involving long-lived gluinos that is complementary to existing techniques at the LHC.

Search for Higgsino pair production in collisions at √s=13 TeV in final states with large missing transverse momentum and two Higgs bosons decaying via H→bb̄

Search for Higgsino pair production in collisions at √s=13 TeV in final states with large missing transverse momentum and two Higgs bosons decaying via H→bb̄

A search for new phenomena in pp collisions at $\sqrt {s} = 13$ TeV in final states with missing transverse momentum and at least one jet using the $α_{T}$ variable

A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13TeV. The analysed data sample, recorded with the CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3 $fb^{−1}$. Several kinematic variables are employed to suppress the dominant background, multijet production, as well as to discriminate between other standard model and new physics processes. The search provides sensitivity to a broad range of new-physics models that yield a stable weakly interacting massive particle. The number of observed candidate events is found to agree with the expected contributions from standard model processes, and the result is interpreted in the mass parameter space of fourteen simplified supersymmetric models that assume the pair production of gluinos or squarks and a range of decay modes. For models that assume gluino pair production, masses up to 1575 and 975GeV are excluded for gluinos and neutralinos, respectively. For models involving the pair production of top squarks and compressed mass spectra, top squark masses up to 400GeV are excluded.

Search for supersymmetry at [Formula: see text]TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector.

A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons (e or mu ) with the same electric charge or at least three isolated leptons. The search also utilises b-tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton–proton collisions at sqrt{s}= 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.2 fb^{-1}. No significant excess over the Standard Model expectation is observed. The results are interpreted in several simplified supersymmetric models and extend the exclusion limits from previous searches. In the context of exclusive production and simplified decay modes, gluino masses are excluded at 95,% confidence level up to 1.1–1.3 TeV for light neutralinos (depending on the decay channel), and bottom squark masses are also excluded up to 540 GeV. In the former scenarios, neutralino masses are also excluded up to 550–850 GeV for gluino masses around 1 TeV.

Production of vector bosons and jets at CMS

The production cross section of highly boosted vector bosons (V = W, Z) recoiling against jets is studied, with CMS data, differentially as function of the transverse momentum and angular correlations of the final state particles. The mechanism of production of heavy-flavoured mesons, containing b or c quarks, in association with vector bosons, W or Z, in the Standard Model is only partially understood. The study of events with one or two well-identified and isolated leptons accompanied by b-jets or b-mesons is therefore crucial to refine the theoretical calculations in perturbative QCD, as well as validate associated Monte Carlo techniques. A measurement of the WZ and ZZ production cross sections in proton-proton collisions at 8 TeV in final states where one Z boson decays to b-tagged jets, while the other gauge boson, either W or Z, is detected through its leptonic decay is also presented.

Measurement of WZ and ZZ production in pp collisions at [Formula: see text] in final states with b-tagged jets.

Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at sqrt{s} = 8 ,text {TeV} in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either mathrm {W}rightarrow mathrm {e}nu , mathrm {mu }nu or mathrm {Z}rightarrow mathrm {e}^+mathrm {e}^-, mathrm {mu ^+}mathrm {mu ^-}, or {nu }overline{nu }). The results are based on data corresponding to an integrated luminosity of 18.9 fb^{-1} collected with the CMS detector at the Large Hadron Collider. The measured cross sections, sigma (mathrm {p}mathrm {p}rightarrow mathrm {W}mathrm {Z}) = 30.7 pm 9.3,text {(stat.)} pm 7.1,text {(syst.)} pm 4.1,text {(th.)} pm 1.0,text {(lum.)} ,text {pb} and sigma (mathrm {p}mathrm {p}rightarrow mathrm {Z}mathrm {Z}) = 6.5 pm 1.7,text {(stat.)} pm 1.0,text {(syst.)} pm 0.9,text {(th.)} pm 0.2,text {(lum.)} ,text {pb} , are consistent with next-to-leading order quantum chromodynamics calculations.

Search for supersymmetry at $\sqrt{s}$ = 8 TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector

AbstractA search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons (eor μ) with the same electric charge, or at least three isolated leptons. The search also utilises jets originating fromb-quarks, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample corresponding to a total integrated luminosity of 20.3 fb−1of$ \sqrt{s} $= 8 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider in 2012. No deviation from the Standard Model expectation is observed. New or significantly improved exclusion limits are set on a wide variety of supersymmetric models in which the lightest squark can be of the first, second or third generations, and in which R-parity can be conserved or violated.

Search for supersymmetry in final states with jets, missing transverse momentum and isolated leptons with the ATLAS detector in 5 fb−1of √s= 8 TeV pp collisions

We present an inclusive search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy p s = 8 TeV in final states with jets, missing transverse momentum and one isolated electron or muon. The search is based on the data from the early 2012 data-taking period, corresponding to an integrated luminosity of 5.8 fb 1 . No excess is observed in the data, and limits on supersymmetry are set in the MSUGRA/ CMSSM model.

Further search for supersymmetry ats=7 TeVin final states with jets, missing transverse momentum, and isolated leptons with the ATLAS detector

This work presents a new inclusive search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy sqrt(s) = 7 TeV in final states with jets, missing transverse momentum and one or more isolated electrons and/or muons. The search is based on data from the full 2011 data-taking period, corresponding to an integrated luminosity of 4.7 inverse fb. Single- and multi-lepton channels are treated together in one analysis. An increase in sensitivity is obtained by simultaneously fitting the number of events in statistically independent signal regions, and the shapes of distributions within those regions. A dedicated signal region is introduced to be sensitive to decay cascades of SUSY particles with small mass differences ("compressed SUSY"). Background uncertainties are constrained by fitting to the jet multiplicity distribution in background control regions. Observations are consistent with Standard Model expectations, and limits are set or extended on a number of SUSY models.