Our study of the spin-parity and tensor structure of the interactions of the recently discovered Higgs boson is performed using the H→ZZ,Zγ*,γ*γ*→4ℓ, H→WW→ℓνℓν, and H→γγ decay modes. The full data ...set recorded by the CMS experiment during the LHC run 1 is used, corresponding to an integrated luminosity of up to 5.1 fb-1 at a center-of-mass energy of 7 TeV and up to 19.7 fb-1 at 8 TeV. A wide range of spin-two models is excluded at a 99% confidence level or higher, or at a 99.87% confidence level for the minimal gravitylike couplings, regardless of whether assumptions are made on the production mechanism. Any mixed-parity spin-one state is excluded in the ZZ and WW modes at a greater than 99.999% confidence level. Under the hypothesis that the resonance is a spin-zero boson, the tensor structure of the interactions of the Higgs boson with two vector bosons ZZ, Zγ, γγ, and WW is investigated and limits on eleven anomalous contributions are set. Furthermore, the tighter constraints on anomalous HVV interactions are obtained by combining the HZZand HWW measurements. All observations are consistent with the expectations for the standard model Higgs boson with the quantum numbers JPC=0++.
A data sample of events from proton–proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the ...CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9
fb
-
1
, and a center-of-mass energy of 13
TeV
. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associated production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500
GeV
for gluinos, 830
GeV
for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350–360 (350–410)
GeV
. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Results are reported on a search for decays of a pseudoscalar A boson into a Z boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the ...h boson decays into b anti-b. The search is based on data from proton-proton collisions at a center-of-mass energy sqrt(s)=8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The h boson is assumed to be the recently discovered standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models.
The double differential cross sections of the Drell–Yan lepton pair (
ℓ
+
ℓ
-
, dielectron or dimuon) production are measured as functions of the invariant mass
m
ℓ
ℓ
, transverse momentum
p
T
(
ℓ
ℓ
...)
, and
φ
η
∗
. The
φ
η
∗
observable, derived from angular measurements of the leptons and highly correlated with
p
T
(
ℓ
ℓ
)
, is used to probe the low-
p
T
(
ℓ
ℓ
)
region in a complementary way. Dilepton masses up to 1
Te
V
are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation of the systematic uncertainty, the ratios of the differential cross sections for various
m
ℓ
ℓ
ranges to those in the Z mass peak interval are presented. The collected data correspond to an integrated luminosity of 36.3
fb
-
1
of proton–proton collisions recorded with the CMS detector at the LHC at a centre-of-mass energy of 13
Te
V
. Measurements are compared with predictions based on perturbative quantum chromodynamics, including soft-gluon resummation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for heavy resonances with masses above 1
TeV
, decaying to final states containing a vector boson and a Higgs boson, is presented. The search considers hadronic decays of the vector boson, ...and Higgs boson decays to b quarks. The decay products are highly boosted, and each collimated pair of quarks is reconstructed as a single, massive jet. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13
TeV
, corresponding to an integrated luminosity of 35.9
fb
-
1
. The data are consistent with the background expectation and are used to place limits on the parameters of a theoretical model with a heavy vector triplet. In the benchmark scenario with mass-degenerate
W
′
and
Z
′
bosons decaying predominantly to pairs of standard model bosons, for the first time heavy resonances for masses as high as 3.3
TeV
are excluded at 95% confidence level, setting the most stringent constraints to date on such states decaying into a vector boson and a Higgs boson.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (=W or Z) in a sample of proton–proton collision events corresponding to an integrated luminosity of ...18.9 fb−1 at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions fa3, is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H→VV channels. Under certain assumptions, fa3ZZ>0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered.
A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one ...such particle and a
boson. The search uses proton-proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137
, at a center-of-mass energy
. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search is reported for pairs of light Higgs bosons (
H
1
) produced in supersymmetric cascade decays in final states with small missing transverse momentum. A data set of LHC
pp
collisions ...collected with the CMS detector at
s
=
13
TeV
and corresponding to an integrated luminosity of 138
fb
-
1
is used. The search targets events where both
H
1
bosons decay into
pairs that are reconstructed as large-radius jets using substructure techniques. No evidence is found for an excess of events beyond the background expectations of the standard model (SM). Results from the search are interpreted in the next-to-minimal supersymmetric extension of the SM, where a “singlino” of small mass leads to squark and gluino cascade decays that can predominantly end in a highly Lorentz-boosted singlet-like
H
1
and a singlino-like neutralino of small transverse momentum. Upper limits are set on the product of the squark or gluino pair production cross section and the square of the
branching fraction of the
H
1
in a benchmark model containing almost mass-degenerate gluinos and light-flavour squarks. Under the assumption of an SM-like
branching fraction,
H
1
bosons with masses in the range 40–120
GeV
arising from the decays of squarks or gluinos with a mass of 1200–2500
GeV
are excluded at 95% confidence level.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for Kaluza-Klein excited vector boson resonances, $W_\mathrm{KK}$, decaying in cascade to three W bosons via a scalar radion $R, W_\mathrm{KK}\to WR \to WWW$, with two or three massive jets ...is presented. The search is performed with proton-proton collision data recorded at $\sqrt{s} =$ 13 TeV, collected by the CMS experiment at the CERN LHC, during 2016-2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. Two final states are simultaneously probed, one where the two W bosons produced by the R decay are reconstructed as separate, large-radius, massive jets, and one where they are merged in a single large-radius jet. The observed data are in agreement with the standard model expectations. Limits are set on the product of the $W_\mathrm{KK}$ resonance cross section and branching fraction to three W bosons in an extended warped extra-dimensional model and are the first of their kind at the LHC.
A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as ...pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1
, collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100
are excluded and further sensitivity is explored towards higher masses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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