Measurements of the associated production of a W boson and a charm ( Formula omitted) quark in proton-proton collisions at a centre-of-mass energy of 8 Formula omitted are reported. The analysis uses ...a data sample corresponding to a total integrated luminosity of 19.7 Formula omitted collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction Formula omitted, where Formula omitted or Formula omitted, and the cross section ratio Formula omitted are measured in a fiducial volume and differentially as functions of the pseudorapidity and of the transverse momentum of the lepton from the W boson decay. The results are compared with theoretical predictions. The impact of these measurements on the determination of the strange quark distribution is assessed.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one ...such particle and a Formula omitted boson. The search uses proton-proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137 Formula omitted, at a center-of-mass energy Formula omitted. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as ...pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1 Formula omitted, collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100 Formula omitted are excluded and further sensitivity is explored towards higher masses.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 Formula omitted, corresponding to an integrated ...luminosity of 35.9 Formula omitted, are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The production of Z boson pairs in proton-proton ( Formula omitted) collisions, Formula omitted, where Formula omitted or Formula omitted, is studied at a center-of-mass energy of 13 Formula omitted ...with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137 Formula omitted, collected during 2016-2018. The Formula omitted production cross section, Formula omitted, measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region Formula omitted is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous Formula omitted and Formula omitted couplings.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search is presented for supersymmetric partners of the top quark (top squarks) in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from Formula ...omittedquarks, and missing transverse momentum. The search uses data from proton-proton collisions at Formula omitted collected with the CMS detector, corresponding to an integrated luminosity of 137 Formula omitted. Hypothetical signal events are efficiently separated from the dominant top quark pair production background with requirements on the significance of the missing transverse momentum and on transverse mass variables. No significant deviation is observed from the expected background. Exclusion limits are set in the context of simplified supersymmetric models with pair-produced lightest top squarks. For top squarks decaying exclusively to a top quark and a lightest neutralino, lower limits are placed at Formula omitted confidence level on the masses of the top squark and the neutralino up to 925 and 450 Formula omitted, respectively. If the decay proceeds via an intermediate chargino, the corresponding lower limits on the mass of the lightest top squark are set up to 850 Formula omitted for neutralino masses below 420 Formula omitted. For top squarks undergoing a cascade decay through charginos and sleptons, the mass limits reach up to 1.4 Formula omitted and 900 Formula omitted respectively for the top squark and the lightest neutralino.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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 Formula omitted at a center-of-mass energy of Formula omitted, 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 Formula omitted for gluinos and Formula omitted for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search is presented for a heavy vector resonance decaying into a Formula omitted boson and the standard model Higgs boson, where the Formula omitted boson is identified through its leptonic decays ...to electrons, muons, or neutrinos, and the Higgs boson is identified through its hadronic decays. The search is performed in a Lorentz-boosted regime and is based on data collected from 2016 to 2018 at the CERN LHC, corresponding to an integrated luminosity of 137 Formula omitted. Upper limits are derived on the production of a narrow heavy resonance Formula omitted, and a mass below 3.5 and 3.7 Formula omitted is excluded at 95% confidence level in models where the heavy vector boson couples predominantly to fermions and to bosons, respectively. These are the most stringent limits placed on the Heavy Vector Triplet Formula omitted model to date. If the heavy vector boson couples exclusively to standard model bosons, upper limits on the product of the cross section and branching fraction are set between 23 and 0.3 Formula omitted for a Formula omitted mass between 0.8 and 4.6 Formula omitted, respectively. This is the first limit set on a heavy vector boson coupling exclusively to standard model bosons in its production and decay.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The rate for Higgs ( Formula omitted) bosons production in association with either one ( Formula omitted) or two ( Formula omitted) top quarks is measured in final states containing multiple ...electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton-proton collisions recorded at a center-of-mass energy of Formula omitted by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137 Formula omitted. The analysis is aimed at events that contain Formula omitted, Formula omitted, or Formula omitted decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among Formula omitted, Formula omitted, and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the Formula omitted and Formula omitted signals correspond to Formula omitted and Formula omitted of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for Formula omitted, and to 1.4 (0.3) for Formula omitted production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling Formula omitted of the Higgs boson to the top quark divided by its SM expectation, Formula omitted, is constrained to be within Formula omitted or Formula omitted, at 95% confidence level. This result is the most sensitive measurement of the Formula omitted production rate to date.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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