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A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb⁻¹, recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level.

 

A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb⁻¹at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z′ boson couplings to a bb quark pair (g_b), an sb quark pair (g_bδ_bs), and any same-flavor charged lepton (g_ℓ) or neutrino pair (g_ν), with|g_ν|=|g_ℓ|. For a Z′ boson with a mass$$ {m}_{{\textrm{Z}}^{\prime }} $$$m_{Z^{\prime }}$= 350 GeV (2 TeV) and|δ_bs|< 0.25, the majority of the parameter space with 0.0057 <|g_ℓ|< 0.35 (0.25 <|g_ℓ|< 0.43) and 0.0079 < |g_b| < 0.46 (0.34 < |g_b| < 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z′ model with parameters consistent with low-energy b → sℓℓmeasurements. In this scenario, most of the allowed parameter space is excluded for a Z′ boson with 350 <$$ {m}_{{\textrm{Z}}^{\prime }} $$$m_{Z^{\prime }}$< 500 GeV, while the constraints are less stringent for higher$$ {m}_{{\textrm{Z}}^{\prime }} $$$m_{Z^{\prime }}$hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date.

 

The mass of the top quark is measured in 36.3$$\,\text {fb}^{-1}$$${\text{fb}}^{-1}$of LHC proton–proton collision data collected with the CMS detector at$$\sqrt{s}=13\,\text {Te}\hspace{-.08em}\text {V} $$$\sqrt{s}=13\text{Te}\text{V}$. The measurement uses a sample of top quark pair candidate events containing one isolated electron or muon and at least four jets in the final state. For each event, the mass is reconstructed from a kinematic fit of the decay products to a top quark pair hypothesis. A profile likelihood method is applied using up to four observables per event to extract the top quark mass. The top quark mass is measured to be$$171.77\pm 0.37\,\text {Ge}\hspace{-.08em}\text {V} $$$171.77\pm 0.37\text{Ge}\text{V}$. This approach significantly improves the precision over previous measurements.

 

A bstract A search for physics beyond the standard model (SM) in the final state with a hadronically decaying tau lepton and a neutrino is presented. This analysis is based on data recorded by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, corresponding to a total integrated luminosity of 138 fb − 1 . The transverse mass spectrum is analyzed for the presence of new physics. No significant deviation from the SM prediction is observed. Limits are set on the production cross section of a W′ boson decaying into a tau lepton and a neutrino. Lower limits are set on the mass of the sequential SM-like heavy charged vector boson and the mass of a quantum black hole. Upper limits are placed on the couplings of a new boson to the SM fermions. Constraints are put on a nonuniversal gauge interaction model and an effective field theory model. For the first time, upper limits on the cross section of t -channel leptoquark (LQ) exchange are presented. These limits are translated into exclusion limits on the LQ mass and on its coupling in the t -channel. The sensitivity of this analysis extends into the parameter space of LQ models that attempt to explain the anomalies observed in B meson decays. The limits presented for the various interpretations are the most stringent to date. Additionally, a model-independent limit is provided. 

A bstract The first measurement of the top quark pair ( $$ \textrm{t}\overline{\textrm{t}} $$ t t ¯ ) production cross section in proton-proton collisions at $$ \sqrt{s} $$ s = 13 . 6 TeV is presented. Data recorded with the CMS detector at the CERN LHC in Summer 2022, corresponding to an integrated luminosity of 1 . 21 fb − 1 , are analyzed. Events are selected with one or two charged leptons (electrons or muons) and additional jets. A maximum likelihood fit is performed in event categories defined by the number and flavors of the leptons, the number of jets, and the number of jets identified as originating from b quarks. An inclusive $$ \textrm{t}\overline{\textrm{t}} $$ t t ¯ production cross section of 881 ± 23 (stat + syst) ± 20 (lumi) pb is measured, in agreement with the standard model prediction of $$ {924}_{-40}^{+32} $$ 924 − 40 + 32 pb.