A search is performed for neutral non-standard-model Higgs bosons decaying to two muons in the context of the minimal supersymmetric standard model (MSSM). Proton-proton collision data recorded by ...the CMS experiment at the CERN Large Hadron Collider at a center-of-mass energy of 13 TeV were used, corresponding to an integrated luminosity of 35.9fb−1. The search is sensitive to neutral Higgs bosons produced via the gluon fusion process or in association with a bb‾ quark pair. No significant deviations from the standard model expectation are observed. Upper limits at 95% confidence level are set in the context of the mhmod+ and phenomenological MSSM scenarios on the parameter tanβ as a function of the mass of the pseudoscalar A boson, in the range from 130 to 600 GeV. The results are also used to set a model-independent limit on the product of the branching fraction for the decay into a muon pair and the cross section for the production of a scalar neutral boson, either via gluon fusion, or in association with b quarks, in the mass range from 130 to 1000 GeV.
Abstract
A measurement is presented of differential cross sections for
t
-channel single top quark and antiquark production in proton–proton collisions at a centre-of-mass energy of 13
$$\,\text ...{Te}\text {V}$$
Te
by the CMS experiment at the LHC. From a data set corresponding to an integrated luminosity of 35.9
$$\,\text {fb}^{-1}$$
fb
-
1
, events containing one muon or electron and two or three jets are analysed. The cross section is measured as a function of the top quark transverse momentum (
$$p_{\mathrm{T}} $$
p
T
), rapidity, and polarisation angle, the charged lepton
$$p_{\mathrm{T}} $$
p
T
and rapidity, and the
$$p_{\mathrm{T}} $$
p
T
of the
$$\text {W}{}{}$$
W
boson from the top quark decay. In addition, the charge ratio is measured differentially as a function of the top quark, charged lepton, and
$$\text {W}{}{}$$
W
boson kinematic observables. The results are found to be in agreement with standard model predictions using various next-to-leading-order event generators and sets of parton distribution functions. Additionally, the spin asymmetry, sensitive to the top quark polarisation, is determined from the differential distribution of the polarisation angle at parton level to be
$$0.440 \pm 0.070$$
0.440
±
0.070
, in agreement with the standard model prediction.
Abstract
A measurement is presented of electroweak (EW) production of a
$$\mathrm{W} $$
W
boson in association with two jets in proton–proton collisions at
$$\sqrt{s}=13\,\text {Te}\text {V} $$
s
=
...13
Te
. The data sample was recorded by the CMS Collaboration at the LHC and corresponds to an integrated luminosity of 35.9
$$\,\text {fb}^{-1}$$
fb
-
1
. The measurement is performed for the
$$\ell \nu $$
ℓ
ν
jj final state (with
$$\ell \nu $$
ℓ
ν
indicating a lepton–neutrino pair, and j representing the quarks produced in the hard interaction) in a kinematic region defined by invariant mass
$$m_\mathrm {jj} >120\,\text {Ge}\text {V} $$
m
jj
>
120
Ge
and transverse momenta
$$p_\mathrm {T j} > 25\,\text {Ge}\text {V} $$
p
T
j
>
25
Ge
. The cross section of the process is measured in the electron and muon channels yielding
$$\sigma _\mathrm {EW}(\mathrm{W} \mathrm {jj})= 6.23 \pm 0.12 \,\text {(stat)} \pm 0.61 \,\text {(syst)} \,\text {pb} $$
σ
EW
(
W
jj
)
=
6.23
±
0.12
(stat)
±
0.61
(syst)
pb
per channel, in agreement with leading-order standard model predictions. The additional hadronic activity of events in a signal-enriched region is studied, and the measurements are compared with predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. Limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are
$$-2.3< c_{{\mathrm{W} \mathrm{W} \mathrm{W}}}/\varLambda ^2 < 2.5\,\text {Te}\text {V} ^{-2}$$
-
2.3
<
c
W
W
W
/
Λ
2
<
2.5
Te
-
2
,
$$-8.8< c_{\mathrm{W}}/\varLambda ^2 < 16\,\text {Te}\text {V} ^{-2}$$
-
8.8
<
c
W
/
Λ
2
<
16
Te
-
2
, and
$$-45< c_{\mathrm{B}}/\varLambda ^2 < 46\,\text {Te}\text {V} ^{-2}$$
-
45
<
c
B
/
Λ
2
<
46
Te
-
2
. These results are combined with the CMS EW
$$\mathrm{Zjj} $$
Zjj
analysis, yielding the constraint on the
$$c_{{\mathrm{W} \mathrm{W} \mathrm{W}}}$$
c
W
W
W
coupling:
$$-1.8< c_{{\mathrm{W} \mathrm{W} \mathrm{W}}}/\varLambda ^2 < 2.0\,\text {Te}\text {V} ^{-2}$$
-
1.8
<
c
W
W
W
/
Λ
2
<
2.0
Te
-
2
.
Abstract
A search for
$$\text {W}\text {W}$$
WW
production from double-parton scattering processes using same-charge electron-muon and dimuon events is reported, based on proton-proton collision data ...collected at a center-of-mass energy of
$$13\,\text {TeV} $$
13
TeV
. The analyzed data set corresponds to an integrated luminosity of
$$77.4{\,\text {fb}^{-1}} $$
77.4
fb
-
1
, collected using the CMS detector at the LHC in 2016 and 2017. Multivariate classifiers are used to discriminate between the signal and the dominant background processes. A maximum likelihood fit is performed to extract the signal cross section. This leads to the first evidence for
$$\text {W}\text {W}$$
WW
production via double-parton scattering, with a significance of 3.9 standard deviations. The measured inclusive cross section is
$$1.41\pm 0.28\,\text {(stat)} \pm 0.28\,\text {(syst)} \,\text {pb} $$
1.41
±
0.28
(stat)
±
0.28
(syst)
pb
.
A search for supersymmetry is presented based on events with at least one photon, jets, and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of 13 ...TeV. The data correspond to an integrated luminosity of 35.9 fb-1 and were recorded at the LHC with the CMS detector in 2016. The analysis characterizes signal-like events by categorizing the data into various signal regions based on the number of jets, the number of $\mathrm {b}$-tagged jets, and the missing transverse momentum. No significant excess of events is observed with respect to the expectations from standard model processes. Limits are placed on the gluino and top squark pair production cross sections using several simplified models of supersymmetric particle production with gauge-mediated supersymmetry breaking. Depending on the model and the mass of the next-to-lightest supersymmetric particle, the production of gluinos with masses as large as 2120 Ge and the production of top squarks with masses as large as 1230 Ge are excluded at 95% confidence level.
Abstract
The mass of the top quark is measured using a sample of
$${{\text {t}}\overline{{\text {t}}}$$
t
t
¯
events collected by the CMS detector using proton-proton collisions at
$$\sqrt{s}=13$$
s
...=
13
$$\,\text {TeV}$$
TeV
at the CERN LHC. Events are selected with one isolated muon or electron and at least four jets from data corresponding to an integrated luminosity of 35.9
$$\,\text {fb}^{-1}$$
fb
-
1
. For each event the mass is reconstructed from a kinematic fit of the decay products to a
$${{\text {t}}\overline{{\text {t}}}$$
t
t
¯
hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in
$${\text {q}} \overline{{\text {q}}} ^\prime $$
q
q
¯
′
decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be
$$172.25 \pm 0.08\,\text {(stat+JSF)} \pm 0.62\,\text {(syst)} \,\text {GeV} $$
172.25
±
0.08
(stat+JSF)
±
0.62
(syst)
GeV
. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of
$${{\text {t}}\overline{{\text {t}}}$$
t
t
¯
production, and no indications of a bias in the measurements are observed.
A study of the associated production of a $\mathrm{Z} $ boson and a charm quark jet ( $\mathrm{Z} + \mathrm{c} $ ), and a comparison to production with a $\mathrm{b} $ quark jet ( $\mathrm{Z} + ...\mathrm{b} $ ), in $\mathrm {p}\mathrm {p}$ collisions at a centre-of-mass energy of 8 $\,\text {TeV}$ are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 $\,\text {fb}^{-1}$ , collected with the CMS detector at the CERN LHC. The $\mathrm{Z} $ boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of $\mathrm{c} $ or $\mathrm{b} $ flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with $p_{\mathrm {T}} ^{\ell } > 20\,\text {GeV} $ , ${|\eta ^{\ell }|} < 2.1$ , $71< m_{\ell \ell } < 111\,\text {GeV} $ , and heavy flavour jets with $p_{\mathrm {T}} ^{\text {jet}} > 25\,\text {GeV} $ and ${|\eta ^{ \text {jet}}|} < 2.5$ . The $\mathrm{Z} + \mathrm{c} $ production cross section is measured to be $\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm{Z} + \mathrm{c} + X) \mathcal {B}(\mathrm{Z} \rightarrow \ell ^+\ell ^-) = 8.8 \pm 0.5\,\text {(stat)} \pm 0.6\,\text {(syst)} \,\text {pb} $ . The ratio of the $\mathrm{Z} + \mathrm{c} $ and $\mathrm{Z} + \mathrm{b} $ production cross sections is measured to be $\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm{Z} + \mathrm{c} + X)/\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm{Z} + \mathrm{b} + X) = 2.0 \pm 0.2\,\text {(stat)} \pm 0.2\,\text {(syst)} $ . The $\mathrm{Z} + \mathrm{c} $ production cross section and the cross section ratio are also measured as a function of the transverse momentum of the $\mathrm{Z} $ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.
The production of jets in association with Z bosons, reconstructed via the mu+mu- and e+e- decay channels, is studied in pp and, for the first time, in PbPb collisions. Both data samples were ...collected by the CMS experiment at the LHC, at a center-of-mass energy of 5.02 TeV. The PbPb collisions were analyzed in the 0-30% centrality range. The back-to-back azimuthal alignment was studied in both pp and PbPb collisions for Z bosons with transverse momentum ptz > 60 GeV/c and a recoiling jet with ptj > 30 GeV/c. The pt imbalance, xjz= ptj/ptz, as well as the average number of jet partners per Z, rjz, were studied in intervals of ptz, in both pp and PbPb collisions. The rjz is found to be smaller in PbPb than in pp collisions, which suggests that in PbPb collisions a larger fraction of partons, associated with the Z bosons, lose energy and fall below the 30 GeV/c ptj threshold.
A search for events containing four top quarks (ttbar-ttbar) is reported from proton-proton collisions recorded by the CMS experiment at sqrt(s) = 13 TeV and corresponding to an integrated luminosity ...of 2.6 inverse femtobarns The analysis considers the single-lepton (e or mu)+jets and the opposite-sign dilepton (mu+mu-, mu+/- e-/+, or e+e-)+jets channels. It uses boosted decision trees to combine information on the global event and jet properties to distinguish between ttbar-ttbar and ttbar production. The number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions, and an upper limit is set on the cross section for ttbar-ttbar production in the standard model of 94 fb at 95% confidence level (10.2 times the prediction), with an expected limit of 118 fb. This is combined with the results from the published CMS search in the same-sign dilepton channel, resulting in an improved limit of 69 fb at 95% confidence level (7.4 times the prediction), with an expected limit of 71 fb. These are the strongest constraints on the rate of ttbar-ttbar production to date.
A search for a signal consistent with the type-III seesaw mechanism in events with three or more electrons or muons is presented. The data sample consists of proton-proton collisions at s=13 TeV ...collected by the CMS experiment at the LHC in 2016 and corresponds to an integrated luminosity of 35.9 fb−1. Selection criteria based on the number of leptons and the invariant mass of oppositely charged lepton pairs are used to distinguish the signal from the standard model background. The observations are consistent with the expectations from standard model processes. The results are used to place limits on the production of heavy fermions of the type-III seesaw model as a function of the branching ratio to each lepton flavor. In the scenario of equal branching fractions to each lepton flavor, heavy fermions with masses below 840 GeV are excluded. This is the most sensitive probe to date of the type-III seesaw mechanism.
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