1,515 research outputs found
Erratum to: Search for dark matter and unparticles in events with a Z boson and missing transverse momentum in proton-proton collisions at √s=13 TeV (JHEP, (2017), 9, (106), 10.1007/JHEP09(2017)106)
In the original paper, figure 10 was incorrect. The correct figure is shown below. Additionally, the unparticle entries in table 3, as well as figure 4 and 5 were labelled with incorrect values of ΛU
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
Combined measurements of Higgs boson couplings in proton- proton collisions at v s=13TeV
Combined measurements of the production and
decay rates of the Higgs boson, as well as its couplings to
vector bosons and fermions, are presented. The analysis uses
the LHC proton–proton collision data set recorded with the
CMS detector in 2016 at √s = 13 TeV, corresponding to
an integrated luminosity of 35.9 fb−1. The combination is
based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and
associated production with a W or Z boson, or a top quarkantiquark pair) and the following decay modes: H → γ γ ,
ZZ, WW, τ τ , bb, and μμ. Searches for invisible Higgs
boson decays are also considered. The best-fit ratio of the
signal yield to the standard model expectation is measured
to be μ = 1.17 ± 0.10, assuming a Higgs boson mass of
125.09 GeV. Additional results are given for various assumptions on the scaling behavior of the production and decay
modes, including generic parametrizations based on ratios
of cross sections and branching fractions or couplings. The
results are compatible with the standard model predictions in
all parametrizations considered. In addition, constraints are
placed on various two Higgs doublet models
Search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at 13 TeV
Results are reported of a search for supersymmetry in final states with photons
and missing transverse momentum in proton-proton collisions at the LHC. The data sample
corresponds to an integrated luminosity of 35.9 fb−1
collected at a center-of-mass energy
of 13 TeV using the CMS detector. The results are interpreted in the context of models of
gauge-mediated supersymmetry breaking. Production cross section limits are set on gluino
and squark pair production in this framework. Gluino masses below 1.86 TeV and squark
masses below 1.59 TeV are excluded at 95% confidence level
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
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
Search for Zγ resonances using leptonic and hadronic final states in proton-proton collisions at s√=13 TeV
A search is presented for resonances decaying to a Z boson and a photon. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1, and collected with the CMS detector at the LHC in 2016. Two decay modes of the Z boson are investigated. In the leptonic channels, the Z boson candidates are reconstructed using electron or muon pairs. In the hadronic channels, they are identified using a large-radius jet, containing either light-quark or b quark decay products of the Z boson, via jet substructure and advanced b quark tagging techniques. The results from these channels are combined and interpreted in terms of upper limits on the product of the production cross section and the branching fraction to Zγ for narrow and broad spin-0 resonances with masses between 0.35 and 4.0 TeV, providing thereby the most stringent limits on such resonances
Measurement of inclusive very forward jet cross sections in proton-lead collisions at √sNN = 5.02 TeV
Measurements of differential cross sections for inclusive very forward jet production in proton-lead collisions as a function of jet energy are presented. The data were collected with the CMS experiment at the LHC in the laboratory pseudorapidity range −6.6 < η < −5.2. Asymmetric beam energies of 4 TeV for protons and 1.58 TeV per nucleon for Pb nuclei were used, corresponding to a center-of-mass energy per nucleon pair of sNN = 5.02 TeV. Collisions with either the proton (p+Pb) or the ion (Pb+p) traveling towards the negative η hemisphere are studied. The jet cross sections are unfolded to stable-particle level cross sections with p T ≳ 3 GeV, and compared to predictions from various Monte Carlo event generators. In addition, the cross section ratio of p+Pb and Pb+p data is presented. The results are discussed in terms of the saturation of gluon densities at low fractional parton momenta. None of the models under consideration describes all the data over the full jet-energy range and for all beam configurations. Discrepancies between the differential cross sections in data and model predictions of more than two orders of magnitude are observed.[Figure not available: see fulltext.]. © 2019, The Author(s)
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
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
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