The performance of missing transverse momentum ( ® pmiss T ) reconstruction algorithms for the CMS experiment is presented, using proton-proton collisions at a center-of-mass energy of 13 TeV, collected at the CERN LHC in 2016. The data sample corresponds to an integrated luminosity of 35.9 fb1. The results include measurements of the scale and resolution of ® pmiss T, and detailed studies of events identified with anomalous ® pmiss T . The performance is presented of a ® pmiss T reconstruction algorithm that mitigates the effects of multiple proton-proton interactions, using the "pileup per particle identification" method. The performance is shown of an algorithm used to estimate the compatibility of the reconstructed ® pmiss T with the hypothesis that it originates from resolution effects. © 2019 CERN for the benefit of the CMS collaboration.

Prafulla Kumar Behera

Department Of Physics

Astrophysics

Tellurium compounds

HIGH ENERGY PHYSICS DETECTOR

Integrated luminosity

Particle identifications

PROTON INTERACTIONS

Proton proton collisions

Reconstruction algorithms

RESOLUTION EFFECTS

TRANSVERSE ENERGY

High energy physics

Fulltext

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IIT Madras

Performance of missing transverse momentum reconstruction in proton-proton collisions at $\sqrt{s} =$ 13 TeV using the CMS detector

Journal of Instrumentation

Two related searches for phenomena beyond the standard model (BSM) are performed using events with hadronic jets and significant transverse momentum imbalance. The results are based on a sample of proton–proton collisions at a center-of-mass energy of 13Te, collected by the CMS experiment at the LHC in 2016–2018 and corresponding to an integrated luminosity of 137fb-1. The first search is inclusive, based on signal regions defined by the hadronic energy in the event, the jet multiplicity, the number of jets identified as originating from bottom quarks, and the value of the kinematic variable MT 2 for events with at least two jets. For events with exactly one jet, the transverse momentum of the jet is used instead. The second search looks in addition for disappearing tracks produced by BSM long-lived charged particles that decay within the volume of the tracking detector. No excess event yield is observed above the predicted standard model background. This is used to constrain a range of BSM models that predict the following: the pair production of gluinos and squarks in the context of supersymmetry models conserving R-parity, with or without intermediate long-lived charginos produced in the decay chain; the resonant production of a colored scalar state decaying to a massive Dirac fermion and a quark; or the pair production of scalar and vector leptoquarks each decaying to a neutrino and a top, bottom, or light-flavor quark. In most of the cases, the results obtained are the most stringent constraints to date. © 2019, CERN for the benefit of the CMS collaboration.

European Physical Journal C

Searches for physics beyond the standard model with the MT 2 variable in hadronic final states with and without disappearing tracks in proton–proton collisions at √s=13Te

A search for long-lived particles decaying to displaced, nonprompt jets and missing transverse momentum is presented. The data sample corresponds to an integrated luminosity of 137 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC in 2016–2018. Candidate signal events containing nonprompt jets are identified using the timing capabilities of the CMS electromagnetic calorimeter. The results of the search are consistent with the background prediction and are interpreted using a gauge-mediated supersymmetry breaking reference model with a gluino next-to-lightest supersymmetric particle. In this model, gluino masses up to 2100, 2500, and 1900 GeV are excluded at 95% confidence level for proper decay lengths of 0.3, 1, and 100 m, respectively. These are the best limits to date for such massive gluinos with proper decay lengths greater than ∼0.5 m. © 2019 The Author

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

Search for long-lived particles using nonprompt jets and missing transverse momentum with proton-proton collisions at s=13TeV

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 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. [Figure not available: see fulltext.]. © 2019, The Author(s).

Journal of High Energy Physics

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

A search is presented for three additional operators that would lead to anomalous WWγ or WWZ couplings with respect to those in the standard model. They are constrained by studying events with two vector bosons; a W boson decaying to eν or μν, and a W or Z boson decaying hadronically, reconstructed as a single, massive, large- radius jet. The search uses a data set of proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 35.9 fb−1. Using the reconstructed diboson invariant mass, 95% confidence intervals are obtained for the anomalous coupling parameters of −1.58 &lt; cWWW/Λ2&lt; 1.59 TeV−2, −2.00 &lt; cW/Λ2&lt; 2.65 TeV−2, and −8.78 &lt; cB/Λ2&lt; 8.54 TeV−2, in agreement with standard model expectations of zero for each parameter. These are the strictest bounds on these parameters to date. [Figure not available: see fulltext.]. © 2019, The Author(s).

Search for anomalous triple gauge couplings in WW and WZ production in lepton + jet events in proton-proton collisions at √s = 13 TeV

A search for anomalous electroweak production of WW, WZ, and ZZ boson pairs in association with two jets in proton-proton collisions at s=13TeV at the LHC is reported. The data sample corresponds to an integrated luminosity of 35.9fb−1 collected with the CMS detector. Events are selected by requiring two jets with large rapidity separation and invariant mass, one or two leptons (electrons or muons), and a W or Z boson decaying hadronically. No excess of events with respect to the standard model background predictions is observed and constraints on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators are reported. Stringent limits on parameters of the effective field theory operators are obtained. The observed 95% confidence level limits for the S0, M0, and T0 operators are −2.7&lt;fS0/Λ4&lt;2.7, −1.0&lt;fM0/Λ4&lt;1.0, and −0.17&lt;fT0/Λ4&lt;0.16, in units of TeV−4. Constraints are also reported on the product of the cross section and branching fraction for vector boson fusion production of charged Higgs bosons as a function of mass from 600 to 2000 GeV. The results are interpreted in the context of the Georgi–Machacek model. © 2019 The Author(s)

Search for anomalous electroweak production of vector boson pairs in association with two jets in proton-proton collisions at 13 TeV

The CMS muon detector system, muon reconstruction software, and high-level trigger underwent significant changes in 2013-2014 in preparation for running at higher LHC collision energy and instantaneous luminosity. The performance of the modified system is studied using proton-proton collision data at center-of-mass energy s=13 TeV, collected at the LHC in 2015 and 2016. The measured performance parameters, including spatial resolution, efficiency, and timing, are found to meet all design specifications and are well reproduced by simulation. Despite the more challenging running conditions, the modified muon system is found to perform as well as, and in many aspects better than, previously. We dedicate this paper to the memory of Prof. Alberto Benvenuti, whose work was fundamental for the CMS muon detector. © 2018 CERN for the benefit of the CMS collaboration..

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at s=13 TeV

The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic τ decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8\TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions. © 2017 CERN.

Journal	Journal of Instrumentation
Publisher	Institute of Physics Publishing
ISSN	17480221
Open Access	No