scholarly journals Search for direct production of electroweakinos in final states with missing transverse momentum and a Higgs boson decaying into photons in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Cross Sections ◽  
Confidence Level ◽  
Production Cross ◽  
Atlas Detector ◽  
Supersymmetric Particle ◽  
Direct Production ◽  
Missing Transverse Momentum ◽  
Upper Limits

Abstract A search for a chargino-neutralino pair decaying via the 125 GeV Higgs boson into photons is presented. The study is based on the data collected between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb−1 of pp collisions at a centre-of-mass energy of 13 TeV. No significant excess over the expected background is observed. Upper limits at 95% confidence level for a massless $$ {\tilde{\chi}}_1^0 $$ χ ˜ 1 0 are set on several electroweakino production cross-sections and the visible cross-section for beyond the Standard Model processes. In the context of simplified supersymmetric models, 95% confidence-level limits of up to 310 GeV in $$ m\left({\tilde{\chi}}_1^{\pm }/{\tilde{\chi}}_2^0\right) $$ m χ ˜ 1 ± / χ ˜ 2 0 , where $$ m\left({\tilde{\chi}}_1^0\right) $$ m χ ˜ 1 0 = 0.5 GeV, are set. Limits at 95% confidence level are also set on the $$ {\tilde{\chi}}_1^{\pm }{\tilde{\chi}}_2^0 $$ χ ˜ 1 ± χ ˜ 2 0 cross-section in the mass plane of $$ m\left({\tilde{\chi}}_1^{\pm }/{\tilde{\chi}}_2^0\right) $$ m χ ˜ 1 ± / χ ˜ 2 0 and $$ m\left({\tilde{\chi}}_1^0\right) $$ m χ ˜ 1 0 , and on scenarios with gravitino as the lightest supersymmetric particle. Upper limits at the 95% confidence-level are set on the higgsino production cross-section. Higgsino masses below 380 GeV are excluded for the case of the higgsino fully decaying into a Higgs boson and a gravitino.

scholarly journals Search for direct production of electroweakinos in final states with one lepton, missing transverse momentum and a Higgs boson decaying into two b-jets in $$pp$$ collisions at $$\sqrt{s}=13$$ TeV with the ATLAS detector

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Transverse Momentum ◽  
Standard Model ◽  
Cross Sections ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Direct Production ◽  
Missing Transverse Momentum ◽  
Higgs Boson Decaying ◽  
The Standard Model

Abstract The results of a search for electroweakino pair production $$pp \rightarrow \tilde{\chi }^\pm _1 \tilde{\chi }^0_2$$pp→χ~1±χ~20 in which the chargino ($$\tilde{\chi }^\pm _1$$χ~1±) decays into a W boson and the lightest neutralino ($$\tilde{\chi }^0_1$$χ~10), while the heavier neutralino ($$\tilde{\chi }^0_2$$χ~20) decays into the Standard Model 125 GeV Higgs boson and a second $$\tilde{\chi }^0_1$$χ~10 are presented. The signal selection requires a pair of b-tagged jets consistent with those from a Higgs boson decay, and either an electron or a muon from the W boson decay, together with missing transverse momentum from the corresponding neutrino and the stable neutralinos. The analysis is based on data corresponding to 139 $$\mathrm {fb}^{-1}$$fb-1 of $$\sqrt{s}=13$$s=13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. No statistically significant evidence of an excess of events above the Standard Model expectation is found. Limits are set on the direct production of the electroweakinos in simplified models, assuming pure wino cross-sections. Masses of $$\tilde{\chi }^{\pm }_{1}/\tilde{\chi }^{0}_{2}$$χ~1±/χ~20 up to 740 GeV are excluded at 95% confidence level for a massless $$\tilde{\chi }^{0}_{1}$$χ~10.

scholarly journals Erratum to: Higgs boson production cross-section measurements and their EFT interpretation in the $$4\ell $$ decay channel at $$\sqrt{s}=$$13 TeV with the ATLAS detector

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Production Cross Section ◽  
Decay Channel ◽  
Production Cross ◽  
Atlas Detector ◽  
Boson Production ◽  
Higgs Boson Production

A Correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-020-8227-9

TRIPLE GAUGE BOSON PRODUCTION IN e+e- COLLISIONS

1991 ◽  
Vol 06 (39) ◽  
pp. 3565-3572
Author(s):  
M. H. NOUS ◽  
M. El-KISHEN ◽  
A. M. ALGELANI
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Cross Section ◽  
Gauge Boson ◽  
Cross Sections ◽  
Production Cross ◽  
Boson Production ◽  
Production Mechanism ◽  
The Standard Model

The production cross-sections for a triple gauge boson has been investigated in both the standard model and the minimal supersymmetric standard model, via e+e-→W+W-Z0. All events that contain the Higgs-boson seem to have no influence in this process. At [Formula: see text], this process could be detected with a reasonable cross-section, the production mechanism in this case will be e+e-→Z0→W+W-→W+W-Z0.

scholarly journals Improved $$(g-2)_\mu $$ measurements and supersymmetry

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Manimala Chakraborti ◽  
Sven Heinemeyer ◽  
Ipsita Saha
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Cross Sections ◽  
Direct Detection ◽  
Production Cross ◽  
High Energy ◽  
Experimental Result ◽  
Supersymmetric Particle ◽  
Negative Results ◽  
Upper Limits

AbstractThe electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM) can account for variety of experimental data. The lighest supersymmetric particle (LSP), which we take as the lightest neutralino, $${\tilde{\chi }}_{1}^0$$ χ ~ 1 0 , can account for the observed Dark Matter (DM) content of the universe via coannihilation with the next-to-LSP (NLSP), while being in agreement with negative results from Direct Detection (DD) experiments. Owing to relatively small production cross-sections a comparably light EW sector of the MSSM is also in agreement with the unsuccessful searches at the LHC. Most importantly, the EW sector of the MSSM can account for the persistent $$3-4\,\sigma $$ 3 - 4 σ discrepancy between the experimental result for the anomalous magnetic moment of the muon, $$(g-2)_\mu $$ ( g - 2 ) μ , and its Standard Model (SM) prediction. Under the assumption that the $${\tilde{\chi }}_{1}^0$$ χ ~ 1 0 provides the full DM relic abundance we first analyze which mass ranges of neutralinos, charginos and scalar leptons are in agreement with all experimental data, including relevant LHC searches. We find an upper limit of $$\sim 600 \,\, \mathrm {GeV}$$ ∼ 600 GeV for the LSP and NLSP masses. In a second step we assume that the new result of the Run 1 of the “MUON G-2” collaboration at Fermilab yields a precision comparable to the existing experimental result with the same central value. We analyze the potential impact of the combination of the Run 1 data with the existing $$(g-2)_\mu $$ ( g - 2 ) μ data on the allowed MSSM parameter space. We find that in this case the upper limits on the LSP and NLSP masses are substantially reduced by roughly $$100 \,\, \mathrm {GeV}$$ 100 GeV . This would yield improved upper limits on these masses of $$\sim 500 \,\, \mathrm {GeV}$$ ∼ 500 GeV . In this way, a clear target could be set for future LHC EW searches, as well as for future high-energy $$e^+e^-$$ e + e -  colliders, such as the ILC or CLIC.

scholarly journals Measurements of production cross sections of the Higgs boson in the four-lepton final state in proton–proton collisions at $$\sqrt{s} = 13\,\text {Te}\text {V} $$

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Transverse Momentum ◽  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Signal Strength ◽  
Boson Production ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

AbstractProduction cross sections of the Higgs boson are measured in the $${\mathrm{H}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} \rightarrow 4\ell $$ H → Z Z → 4 ℓ ($$\ell ={\mathrm{e}},{{{\upmu }}_{\mathrm{}}^{\mathrm{}}} $$ ℓ = e , μ ) decay channel. A data sample of proton–proton collisions at a center-of-mass energy of 13$$\,\text {Te}\text {V}$$ Te , collected by the CMS detector at the LHC and corresponding to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 is used. The signal strength modifier $$\mu $$ μ , defined as the ratio of the Higgs boson production rate in the $$4\ell $$ 4 ℓ channel to the standard model (SM) expectation, is measured to be $$\mu =0.94 \pm 0.07 \,\text {(stat)} ^{+0.09}_{-0.08} \,\text {(syst)} $$ μ = 0.94 ± 0.07 (stat) - 0.08 + 0.09 (syst) at a fixed value of $$m_{{\mathrm{H}}} = 125.38\,\text {Ge}\text {V} $$ m H = 125.38 Ge . The signal strength modifiers for the individual Higgs boson production modes are also reported. The inclusive fiducial cross section for the $${\mathrm{H}} \rightarrow 4\ell $$ H → 4 ℓ process is measured to be $$2.84^{+0.23}_{-0.22} \,\text {(stat)} ^{+0.26}_{-0.21} \,\text {(syst)} \,\text {fb} $$ 2 . 84 - 0.22 + 0.23 (stat) - 0.21 + 0.26 (syst) fb , which is compatible with the SM prediction of $$2.84 \pm 0.15 \,\text {fb} $$ 2.84 ± 0.15 fb for the same fiducial region. Differential cross sections as a function of the transverse momentum and rapidity of the Higgs boson, the number of associated jets, and the transverse momentum of the leading associated jet are measured. A new set of cross section measurements in mutually exclusive categories targeted to identify production mechanisms and kinematical features of the events is presented. The results are in agreement with the SM predictions.

A SEARCH FOR HIGGS DECAYS TO WW* AT DØ

2005 ◽  
Vol 20 (15) ◽  
pp. 3297-3301
Author(s):  
◽  
AMBER JENKINS
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Confidence Level ◽  
Production Cross Section ◽  
Production Cross ◽  
Branching Ratio ◽  
Final States ◽  
Theoretical Predictions ◽  
Integrated Luminosity

A search for the Higgs boson in the channels [Formula: see text] at DØ is described. The data, corresponding to an integrated luminosity of up to 177 pb-1, are compared to theoretical predictions. No excess of events above the expected background is observed in any of the leptonic final states. Limits on the production cross-section times branching ratio, σ × BR(H → WW*), are therefore set at the 95% Confidence Level.

scholarly journals Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at $$\sqrt{s} = 13$$ TeV with the ATLAS detector

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Hadron Collider ◽  
Inclusive Cross Section ◽  
Atlas Detector ◽  
Proton Collision ◽  
Proton Proton ◽  
Theoretical Predictions

AbstractMeasurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson ($$t{\bar{t}}Z$$ t t ¯ Z ) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on $$\sqrt{s} = 13$$ s = 13  TeV proton–proton collision data with an integrated luminosity of 139 $$\hbox {fb}^{-1}$$ fb - 1 , recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be $$\sigma _{t{\bar{t}}Z} = 0.99 \pm 0.05$$ σ t t ¯ Z = 0.99 ± 0.05  (stat.) $$\pm \, 0.08$$ ± 0.08  (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the $$t{\bar{t}}Z$$ t t ¯ Z system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a $$\chi ^{2}/$$ χ 2 / ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.

scholarly journals Search for electroweak production of charginos and sleptons decaying into final states with two leptons and missing transverse momentum in $$\sqrt{s}=13$$ $$\text {TeV}$$ pp collisions using the ATLAS detector

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Atlas Detector ◽  
Supersymmetric Particle ◽  
Final States ◽  
Proton Proton ◽  
Direct Production ◽  
Proton Collisions ◽  
Missing Transverse Momentum ◽  
The Masses ◽  
Proton Proton Collisions

Abstract A search for the electroweak production of charginos and sleptons decaying into final states with two electrons or muons is presented. The analysis is based on 139 fb$$^{-1}$$-1 of proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider at $$\sqrt{s}=13$$s=13 $$\text {TeV}$$TeV. Three R-parity-conserving scenarios where the lightest neutralino is the lightest supersymmetric particle are considered: the production of chargino pairs with decays via either W bosons or sleptons, and the direct production of slepton pairs. The analysis is optimised for the first of these scenarios, but the results are also interpreted in the others. No significant deviations from the Standard Model expectations are observed and limits at 95% confidence level are set on the masses of relevant supersymmetric particles in each of the scenarios. For a massless lightest neutralino, masses up to 420 $$\text {Ge}\text {V}$$Ge are excluded for the production of the lightest-chargino pairs assuming W-boson-mediated decays and up to 1 $$\text {TeV}$$TeV for slepton-mediated decays, whereas for slepton-pair production masses up to 700 $$\text {Ge}\text {V}$$Ge are excluded assuming three generations of mass-degenerate sleptons.

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