87 research outputs found

    Search for a low-mass pseudoscalar Higgs boson produced in association with a bb⁻ pair in pp collisions at √s=8 TeV

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    A search is reported for a light pseudoscalar Higgs boson decaying to a pair of tau leptons, produced in association with a b (b) over bar pair, in the context of two-Higgs-doublet models. The results are based on pp collision data at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC and corresponding to an integrated luminosity of 19.7 fb(-1). Pseudoscalar boson masses between 25 and 80 GeV are probed. No evidence for a pseudoscalar boson is found and upper limits are set on the product of cross section and branching fraction to tau pairs between 7 and 39 pb at the 95% confidence level. This excludes pseudoscalar A bosons with masses between 25 and 80 GeV, with SM-like Higgs boson negative couplings to down-type fermions, produced in association with bb pairs, in Type II, two-Higgs-doublet models. (C) 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommonnorg/licensesiby/4.01)

    Search for single production of scalar leptoquarks in proton-proton collisions at root s=8 TeV

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    Correction DOI:10.1103/PhysRevD.95.039906Peer reviewe

    Search for vectorlike charge 2/3 T quarks in proton-proton collisions at root(s)=8 TeV

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    Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

    Pseudorapidity distribution of charged hadrons in proton-proton collisions at root s=13TeV

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    Search for pair-produced vectorlike B quarks in proton-proton collisions at root s=8 TeV

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    Search for third-generation scalar leptoquarks in the tτ channel in proton-proton collisions at √s=8 TeV

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    A search for pair production of third-generation scalar leptoquarks decaying to top quark and τ lepton pairs is presented using proton-proton collision data at a center-of-mass energy of s = 8 s√=8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb −1 . The search is performed using events that contain an electron or a muon, a hadronically decaying τ lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a τ lepton, the existence of pair produced, charge −1 / 3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a τ lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling λ 333 ′

    Transverse momentum spectra of inclusive b jets in pPb collisions at √sNN=5.02 TeV

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    We present a measurement of b jet transverse momentum (pT) spectra in proton-lead (pPb) collisions using a dataset corresponding to about 35 nb−1 collected with the CMS detector at the LHC. Jets from b quark fragmentation are found by exploiting the long lifetime of hadrons containing a b quark through tagging methods using distributions of the secondary vertex mass and displacement. Extracted cross sections for b jets are scaled by the effective number of nucleon–nucleon collisions and are compared to a reference obtained from pythia simulations of pp collisions. The pythia -based estimate of the nuclear modification factor is found to be 1.22±0.15(stat+syst pPb)±0.27(syst pythia) averaged over all jets with pT between 55 and 400 GeV/c and with |ηlab|<2 . We also compare this result to predictions from models using perturbative calculations in quantum chromodynamics

    Search for excited leptons in proton-proton collisions at root s=8 TeV

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    Search for W ' -> tb in proton-proton collisions at root s=8 TeV

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