A
bstract
We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the ...Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the most stringent constraints. The main novelties of our study are the inclusion of SMEFT effects in non-resonant diagrams and in irreducible QCD backgrounds, and an exhaustive template analysis of optimal observables for each operator and process considered. We also assess for the first time the sensitivity of vector-boson-scattering searches in semileptonic final states.
A
bstract
We present the first parton-level study of anomalous effects in triboson production in both fully and semi-leptonic channels in proton-proton collisions at 13 TeV at the Large Hadron ...Collider (LHC). The sensitivity to anomalies induced by a minimal set of bosonic dimension-6 operators from the Warsaw basis is evaluated with specific analyses for each final state. A likelihood-based strategy is employed to assess the most sensitive kinematic observables per channel, where the contribution of Effective Field Theory operators is parameterized at either the linear or quadratic level. The impact of the mutual interference terms of pairs of operators on the sensitivity is also examined. This benchmark study explores the complementarity and overlap in sensitivity between different triboson measurements and paves the way for future analyses at the LHC experiments. The statistical combination of the considered final states allows setting stringent bounds on five bosonic Wilson coefficients.
A
bstract
A search is presented for new particles produced at the LHC in proton-proton collisions at
s
= 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis ...is based on a data sample corresponding to an integrated luminosity of 101 fb
−
1
, collected in 2017–2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb
−
1
, collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.
A
bstract
Three searches are presented for signatures of physics beyond the standard model (SM) in
ττ
final states in proton-proton collisions at the LHC, using a data sample collected with the CMS ...detector at
s
= 13 TeV, corresponding to an integrated luminosity of 138 fb
−
1
. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into
τ
leptons and the cross sections for the production of a new boson
ϕ
, in addition to the H(125) boson, via gluon fusion (gg
ϕ
) or in association with b quarks, ranging from
O
(10 pb) for a mass of 60 GeV to 0.3 fb for a mass of 3.5 TeV each. The data reveal two excesses for gg
ϕ
production with local
p
-values equivalent to about three standard deviations at
m
ϕ
= 0
.
1 and 1.2 TeV. In a search for
t
-channel exchange of a vector leptoquark U
1
, 95% CL upper limits are set on the dimensionless U
1
leptoquark coupling to quarks and
τ
leptons ranging from 1 for a mass of 1 TeV to 6 for a mass of 5 TeV, depending on the scenario. In the interpretations of the
M
h
125
and
M
h
,
EFT
125
minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below 350 GeV are excluded at 95% CL.
A
bstract
A search for heavy neutral leptons (HNLs), the right-handed Dirac or Majorana neutrinos, is performed in final states with three charged leptons (electrons or muons) using proton-proton ...collision data collected by the CMS experiment at
s
= 13 TeV at the CERN LHC. The data correspond to an integrated luminosity of 138 fb
−
1
. The HNLs could be produced through mixing with standard model neutrinos
ν
. For small values of the HNL mass (
<
20 GeV) and the square of the HNL-
ν
mixing parameter (10
−
7
–10
−
2
), the decay length of these particles can be large enough so that the secondary vertex of the HNL decay can be resolved with the CMS silicon tracker. The selected final state consists of one lepton emerging from the primary proton-proton collision vertex, and two leptons forming a displaced, secondary vertex. No significant deviations from the standard model expectations are observed, and constraints are obtained on the HNL mass and coupling strength parameters, excluding previously unexplored regions of parameter space in the mass range 1–20 GeV and squared mixing parameter values as low as 10
−
7
.
Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width—related to its lifetime—is an important parameter. One way to ...determine this quantity is to measure its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here we report evidence for such off-shell contributions to the production cross-section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval 0.0061, 2.0 at the 95% confidence level. The scenario with no off-shell contribution is excluded at a p-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as ΓH=3.2−1.7+2.4MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs.The CMS Collaboration reports evidence for off-shell Higgs boson contributions in the production of Z boson pairs, and measures the width of the Higgs boson, which is inversely related to its lifetime.
The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the ...searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140 fb^{-1} for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.
A
bstract
The first measurement of the
CP
structure of the Yukawa coupling between the Higgs boson and
τ
leptons is presented. The measurement is based on data collected in proton-proton collisions ...at
s
= 13 TeV by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb
−
1
. The analysis uses the angular correlation between the decay planes of
τ
leptons produced in Higgs boson decays. The effective mixing angle between
CP
-even and
CP
-odd
τ
Yukawa couplings is found to be
−
1
±
19°, compared to an expected value of 0
±
21° at the 68.3% confidence level. The data disfavour the pure
CP
-odd scenario at 3.0 standard deviations. The results are compatible with predictions for the standard model Higgs boson.
The hockey-stick surgical incision is becoming more popular than the oblique incision for kidney transplantations. Both incisions are convenient and comfortable. Both have some drawbacks, such as ...muscle denervation for the former, or section of lateral muscles for the latter. In this retrospective study, we compared these incisions with regard to the incidence of long-term complications, such as postincisional hernia, relaxation of the abdominal wall, and a poor cosmetic result. One hundred patients (50 of each type) were evaluated at an average of 4.5 years after transplantation (3 months–15 years). Occurrence of incisional hernia was 16% in the former (8 cases) versus 4% in the latter (2 cases: X
2 = 4;
P < .05). A major relaxation of the abdominal wall was found in 24% of the former (12 cases) versus 8% of the latter (4 cases) (X
2 = 4.76;
P < .05). These complications were not correlated with age, sex, weight, side of transplant, or immunosuppressive drugs. In the former patients with hockey-stick incisions, the overall cosmetic results were poor, because in most cases the incision had been prolonged upward, above the transverse umbilical line, even as high as the costal arch. In 20% of the former patients with hockey-stick incisions, the scar had widened, particularly in the upper vertical branch of the J incision. We conclude that the final outcome of the oblique surgical incision was better than the hockey-stick incision because of the lower incidence of hernia and abdominal wall relaxation and the more favorable cosmetic results.
A
bstract
A search for long-lived particles decaying into muon pairs is performed using proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in ...2017 and 2018, corresponding to an integrated luminosity of 101 fb
−
1
. The data sets used in this search were collected with a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by retaining a reduced amount of information, in order to explore otherwise inaccessible phase space at low dimuon mass and nonzero displacement from the primary interaction vertex. No significant excess of events beyond the standard model expectation is found. Upper limits on branching fractions at 95% confidence level are set on a wide range of mass and lifetime hypotheses in beyond the standard model frameworks with the Higgs boson decaying into a pair of long-lived dark photons, or with a long-lived scalar resonance arising from a decay of a b hadron. The limits are the most stringent to date for substantial regions of the parameter space. These results can be also used to constrain models of displaced dimuons that are not explicitly considered in this paper.
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