A
bstract
A search is presented for decays beyond the standard model of the 125 GeV Higgs bosons to a pair of light bosons, based on models with extended scalar sectors. Light boson masses between 5 ...and 62.5 GeV are probed in final states containing four
τ
leptons, two muons and two b quarks, or two muons and two
τ
leptons. The results are from data in proton-proton collisions corresponding to an integrated luminosity of 19.7 fb
−1
, accumulated by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV. No evidence for such exotic decays is found in the data. Upper limits are set on the product of the cross section and branching fraction for several signal processes. The results are also compared to predictions of two-Higgs-doublet models, including those with an additional scalar singlet.
The differential cross section and charge asymmetry for inclusive
p
p
→
W
±
+
X
→
μ
±
ν
+
X
production at
s
=
8
TeV
are measured as a function of muon pseudorapidity. The data sample corresponds to ...an integrated luminosity of 18.8
fb
-
1
recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable
x
from
10
-
3
to
10
-
1
.
A search for pair production of heavy scalar leptoquarks (LQs), each decaying into a top quark and a
τ
lepton, is presented. The search considers final states with an electron or a muon, one or two
τ
...leptons that decayed to hadrons, and additional jets. The data were collected in 2016 in proton–proton collisions at
s
=
13
Te
with the CMS detector at the LHC, and correspond to an integrated luminosity of 35.9
fb
-
1
. No evidence for pair production of LQs is found. Assuming a branching fraction of unity for the decay
LQ
→
t
τ
, upper limits on the production cross section are set as a function of LQ mass, excluding masses below 900
Ge
at 95% confidence level. These results provide the most stringent limits to date on the production of scalar LQs that decay to a top quark and a
τ
lepton.
A
bstract
A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 ± 0.5 fb
−1
collected with the CMS detector in proton-proton collisions ...at
s
=
8
,TeV. The charged Higgs boson is searched for in top quark decays for
m
H
± <
m
t
−
m
b
, and in the direct production pp → t(b)H
±
for
m
H
± >
m
t
−
m
b
. The H
±
→
τ
±
ν
τ
and H
±
→ tb decay modes in the final states
τ
h
+jets,
μτ
h
,
ℓ
+jets, and
ℓℓ
’ (
ℓ
=e,
μ
) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction
ℬ
t
→
H
±
b
ℬ
H
±
→
τ
±
ν
τ
=
1.2
−
0.15
%
is obtained in the mass range
m
H
± = 80–160 GeV, while the upper limit on the cross section times branching fraction
σ
pp
→
t
b
H
±
ℬ
H
±
→
τ
±
ν
τ
=
0.38
−
0.025
pb is set in the mass range
m
H
+ = 180–600 GeV. Here,
σ
(pp → t(b)H
±
) stands for the cross section sum
σ
pp
→
t
¯
b
H
+
+
σ
pp
→
t
b
¯
H
−
. Assuming
ℬ
H
±
→
t
b
=
1
, an upper limit on
σ
(pp → t(b)H
±
) of 2.0–0.13 pb is set for
m
H
± = 180–600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the
m
H
±−tan
β
parameter space in different MSSM benchmark scenarios.
A search for standard model production of four top quarks (
t
t
¯
t
t
¯
) is reported using events containing at least three leptons (
e
,
μ
) or a same-sign lepton pair. The events are produced in ...proton–proton collisions at a center-of-mass energy of 13
TeV
at the LHC, and the data sample, recorded in 2016, corresponds to an integrated luminosity of 35.9
fb
-
1
. Jet multiplicity and flavor are used to enhance signal sensitivity, and dedicated control regions are used to constrain the dominant backgrounds. The observed and expected signal significances are, respectively, 1.6 and 1.0 standard deviations, and the
t
t
¯
t
t
¯
cross section is measured to be
16
.
9
-
11.4
+
13.8
fb
, in agreement with next-to-leading-order standard model predictions. These results are also used to constrain the Yukawa coupling between the top quark and the Higgs boson to be less than 2.1 times its expected standard model value at 95% confidence level.
A search for a heavy scalar boson H decaying into a pair of lighter standard-model-like 125 GeV Higgs bosons hh and a search for a heavy pseudoscalar boson A decaying into a Z and an h boson are ...presented. The searches are performed on a data set corresponding to an integrated luminosity of 19.7 fb-1 of pp collision data at a centre-of-mass energy of 8 TeV, collected by CMS in 2012. A final state consisting of two τ leptons and two b jets is used to search for the H → hh decay. A final state consisting of two τ leptons from the h boson decay, and two additional leptons from the Z boson decay, is used to search for the decay A → Zh. The results are interpreted in the context of two-Higgs-doublet models. No excess is found above the standard model expectation and upper limits are set on the heavy boson production cross sections in the mass ranges 260 < mH < 350 GeV and 220 < mA < 350 GeV.
A top quark mass measurement is performed using
35.9
fb
-
1
of LHC proton–proton collision data collected with the CMS detector at
s
=
13
TeV
. The measurement uses the
t
t
¯
all-jets final state. A ...kinematic fit is performed to reconstruct the decay of the
t
t
¯
system and suppress the multijet background. Using the ideogram method, the top quark mass (
m
t
) is determined, simultaneously constraining an additional jet energy scale factor (
JSF
). The resulting value of
m
t
=
172.34
±
0.20
(stat+JSF)
±
0.70
(syst)
GeV
is in good agreement with previous measurements. In addition, a combined measurement that uses the
t
t
¯
lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an
m
t
measurement of
172.26
±
0.07
(stat+JSF)
±
0.61
(syst)
GeV
. This is the first combined
m
t
extraction from the lepton+jets and all-jets channels through a single likelihood function.
The WZ production cross section in proton–proton collisions at s=13 TeV is measured with the CMS experiment at the LHC using a data sample corresponding to an integrated luminosity of 2.3 fb−1. The ...measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′, where ℓ,ℓ′=e,μ. The measured cross section for the range 60<mℓ′ℓ′<120 GeV is σ(pp→WZ)=39.9±3.2(stat) (syst)−3.1+2.9±0.4(theo)±1.3(lumi) pb, consistent with the standard model prediction.
The normalized differential cross section for top quark pair (
t
t
¯
) production is measured in pp collisions at a centre-of-mass energy of 8
TeV
at the CERN LHC using the CMS detector in data ...corresponding to an integrated luminosity of 19.7
fb
-
1
. The measurements are performed in the lepton
+
jets (
e
/
μ
+
jets) and in the dilepton (
e
+
e
-
,
μ
+
μ
-
, and
e
±
μ
∓
) decay channels. The
t
t
¯
cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the
t
t
¯
system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions.
PDF
