Fragmentation of J/psi in jets in pp collisions at root s=5.02 TeV Batoul Diab for the CMS collaboration

The fragmentation of jets containing a J/ψ meson is studied in √s = 5.02 TeV pp data using an integrated luminosity of L = 27.39 pb−1. The fraction of the jet transverse momentum pT,jet carried by the J/ψ is measured for prompt J/ψ and J/ψ coming from b hadron decays, named nonprompt. Whereas the fragmentation function of nonprompt J/ψ is well-modeled by simulations using a Monte Carlo generator, the prompt J/ψ are found to be accompanied by a larger level of jet activity. The fraction of J/ψ mesons that are produced inside a jet is also reported, and found to be larger in data than in simulation, for both prompt and nonprompt J/ψ

Search for the associated production of the Higgs boson and a vector boson in proton-proton collisions at √s = 13 TeV via Higgs boson decays to τ leptons

A search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of τ leptons is performed. A data sample of proton-proton collisions collected at √ s = 13 TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb−1 . The signal strength is measured relative to the expectation for the standard model Higgs boson, yielding µ = 2.5 +1.4 −1.3 . These results are combined with earlier CMS measurements targeting Higgs boson decays to a pair of τ leptons, performed with the same data set in the gluon fusion and vector boson fusion production modes. The combined signal strength is µ = 1.24+0.29 −0.27 (1.00+0.24 −0.23 expected), and the observed significance is 5.5 standard deviations (4.8 expected) for a Higgs boson mass of 125 GeV

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model ττ backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed µµ events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at √ s = 13 TeV corresponding to an integrated luminosity of 41.5 fb−1

Measurement of the energy density as a function of pseudorapidity in proton-proton collisions at root s=13 TeV

A measurement of the energy density in proton– proton collisions at a centre-of-mass energy of √s = 13 TeV is presented. The data have been recorded with the CMS experiment at the LHC during low luminosity operations in 2015. The energy density is studied as a function of pseudorapidity in the ranges − 6.6 <η< − 5.2 and 3.15 < |η| < 5.20. The results are compared with the predictions of several models. All the models considered suggest a different shape of the pseudorapidity dependence compared to that observed in the data. A comparison with LHC proton–proton collision data at √s = 0.9 and 7 TeV confirms the compatibility of the data with the hypothesis of limiting fragmentation

Combination of searches for Higgs Boson pair production in proton-proton collisions at s =13 TeV

This Letter describes a search for Higgs boson pair production using the combined results from four final states: bbγγ, bbττ, bbbb, and bbVV, where V represents a W or Z boson. The search is performed using data collected in 2016 by the CMS experiment from LHC proton-proton collisions at s=13 TeV, corresponding to an integrated luminosity of 35.9 fb-1. Limits are set on the Higgs boson pair production cross section. A 95% confidence level observed (expected) upper limit on the nonresonant production cross section is set at 22.2 (12.8) times the standard model value. A search for narrow resonances decaying to Higgs boson pairs is also performed in the mass range 250-3000 GeV. No evidence for a signal is observed, and upper limits are set on the resonance production cross section

Search for charged Higgs bosons in the H± → τ ± ντ decay channel in proton-proton collisions at √s = 13 TeV

A search is presented for charged Higgs bosons in the H± → τ ± ντ decay mode in the hadronic final state and in final states with an electron or a muon. The search is based on proton-proton collision data recorded by the CMS experiment in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1 . The results agree with the background expectation from the standard model. Upper limits at 95% confidence level are set on the production cross section times branching fraction to τ ± ντ for an H± in the mass range of 80 GeV to 3 TeV, including the region near the top quark mass. The observed limit ranges from 6 pb at 80 GeV to 5 fb at 3 TeV. The limits are interpreted in the context of the minimal supersymmetric standard model m mod− h scenario

Search for vector-like quarks in events with two oppositely charged leptons and jets in proton–proton collisions at √s = 13 TeV

A search for the pair production of heavy vectorlike partners T and B of the top and bottom quarks has been performed by the CMS experiment at the CERN LHC using proton–proton collisions at √s = 13 TeV. The data sample was collected in 2016 and corresponds to an integrated luminosity of 35.9 fb−1. Final states studied for TT production include those where one of the T quarks decays via T → tZ and the other via T → bW, tZ, or tH, where H is a Higgs boson. For the BB case, final states include those where one of the B quarks decays via B → bZ and the other B → tW, bZ, or bH. Events with two oppositely charged electrons or muons, consistent with coming from the decay of a Z boson, and jets are investigated. The number of observed events is consistent with standard model background estimations. Lower limits at 95% confidence level are placed on the masses of the T and B quarks for a range of branching fractions. Assuming 100% branching fractions for T → tZ, and B → bZ, T and B quark mass values below 1280 and 1130 GeV, respectively, are excluded

Measurement of exclusive rho(770)(0) photoproduction in ultraperipheral pPb collisions at root s(NN)=5.02 TeV

Exclusive ρ(770) 0 photoproduction is measured for the first time in ultraperipheral pPb collisions at √s NN = 5.02 TeV with the CMS detector. The cross section σ (γp → ρ(770) 0 p) is 11.0 ± 1.4 (stat) ± 1.0 (syst) μb at �Wγ p � = 92.6 GeV for photon–proton centre-of-mass energies Wγ p between 29 and 213 GeV. The differential cross section dσ/d|t| is measured in the interval 0.025 < |t| < 1 GeV2 as a function of Wγ p , where t is the squared four-momentum transfer at the proton vertex. The results are compared with previous measurements and theoretical predictions. The measured cross section σ (γp → ρ(770) 0 p) has a power-law dependence on the photon–proton centre-of-mass, consistent with electron–proton collision measurements performed at HERA. The Wγ p dependence of the exponential slope of the differential cross section dσ/d|t| is also measure

Measurement of the Z/gamma* -> tau tau cross section in pp collisions at root s=13 TeV and validation of tau lepton analysis techniques

A measurement is presented of the Z/γ ∗ → τ τ cross section in pp collisions at √s = 13 TeV, using data recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 2.3 fb−1. The product of the inclusive cross section and branching fraction is measured to be σ (pp → Z/γ ∗+X) B(Z/γ ∗ → ττ) = 1848 ± 12 (stat) ± 67 (syst + lumi) pb, in agreement with the standard model expectation, computed at next-to-next-to-leading order accuracy in perturbative quantum chromodynamics. The measurement is used to validate new analysis techniques relevant for future measurements of τ lepton production. The measurement also provides the reconstruction efficiency and energy scale for τ decays to hadrons + ντ final states, determined with respective relative uncertainties of 2.2 and 0.9