scholarly journals Measurement of cross sections and couplings of the Higgs boson in fermionic decay modes with the ATLAS detector

2018 ◽  
Vol 182 ◽  
pp. 02119
Author(s):  
Liaoshan Shi
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Cross Sections ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Proton Collision ◽  
Proton Proton ◽  
Decay Modes ◽  
Proton Proton Collision ◽  
The Cross

In this report, we present the latest ATLAS results on the measurement of the cross sections and couplings of the Higgs boson in the fermionic decay modes, H → μ+μ-, H → τ+τ- and H → bb. The searches are performed with proton-proton collision data delivered by the Large Hadron Collider during Run 1 and the first two years of Run 2 at √s = 7, 8 and 13 TeV.

scholarly journals Measurements of the Higgs boson inclusive and differential fiducial cross sections in the 4$$\ell $$ decay channel at $$\sqrt{s}$$ = 13 TeV

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Decay Channel ◽  
Standard Model Prediction ◽  
Hadron Collider ◽  
Proton Collision ◽  
Proton Proton ◽  
The Standard Model ◽  
Proton Proton Collision

AbstractInclusive and differential fiducial cross sections of the Higgs boson are measured in the $$H \rightarrow ZZ^{*} \rightarrow 4\ell $$ H → Z Z ∗ → 4 ℓ ($$\ell = e,\mu $$ ℓ = e , μ ) decay channel. The results are based on proton−proton collision data produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector from 2015 to 2018, equivalent to an integrated luminosity of 139 $$\hbox {fb}^{-1}$$ fb - 1 . The inclusive fiducial cross section for the $$H \rightarrow ZZ^{*} \rightarrow 4\ell $$ H → Z Z ∗ → 4 ℓ process is measured to be $$\sigma _\mathrm {fid} = 3.28 \pm 0.32$$ σ fid = 3.28 ± 0.32  fb, in agreement with the Standard Model prediction of $$\sigma _\mathrm {fid, SM} = 3.41 \pm 0.18 $$ σ fid , SM = 3.41 ± 0.18  fb. Differential fiducial cross sections are measured for a variety of observables which are sensitive to the production and decay of the Higgs boson. All measurements are in agreement with the Standard Model predictions. The results are used to constrain anomalous Higgs boson interactions with Standard Model particles.

scholarly journals Searches for exotic phenomena with the ATLAS detector

2015 ◽  
Vol 39 ◽  
pp. 1560094
Author(s):  
Patrick Czodrowski
Keyword(s):  
Large Hadron Collider ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Proton Collision ◽  
Proton Proton ◽  
Atlas Experiment ◽  
Proton Proton Collision ◽  
New Phenomena

Recent results of searches for exotic phenomena (new phenomena other than Supersymmetry) with the ATLAS experiment at the Large Hadron Collider conducted with proton–proton collision data at [Formula: see text][Formula: see text]TeV taken 2012 were presented.

scholarly journals Measurements of inclusive and differential cross-sections of combined $$ t\overline{t}\gamma $$ and tWγ production in the eμ channel at 13 TeV with the ATLAS detector

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Theoretical Calculations ◽  
Top Quarks ◽  
Atlas Detector ◽  
Proton Collision ◽  
Differential Cross Sections ◽  
Proton Proton ◽  
Fiducial Volume ◽  
Proton Proton Collision

Abstract Inclusive and differential cross-sections for the production of top quarks in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 139 fb−1. The data were collected by the ATLAS detector at the LHC during Run 2 between 2015 and 2018 at a centre-of-mass energy of 13 TeV. The measurements are performed in a fiducial volume defined at parton level. Events with exactly one photon, one electron and one muon of opposite sign, and at least two jets, of which at least one is b-tagged, are selected. The fiducial cross-section is measured to be $$ {39.6}_{-2.3}^{+2.7} $$ 39.6 − 2.3 + 2.7 fb. Differential cross-sections as functions of several observables are compared with state-of-the-art Monte Carlo simulations and next-to-leading-order theoretical calculations. These include cross-sections as functions of photon kinematic variables, angular variables related to the photon and the leptons, and angular separations between the two leptons in the event. All measurements are in agreement with the predictions from the Standard Model.

scholarly journals Search for rare and exotic Higgs Boson decay modes

2018 ◽  
Vol 182 ◽  
pp. 02123
Author(s):  
Junquan Tao
Keyword(s):  
Higgs Boson ◽  
New Physics ◽  
Proton Collision ◽  
Proton Proton ◽  
Decay Modes ◽  
Higgs Decay ◽  
Proton Proton Collision ◽  
8 Tev ◽  
Invisible Decays ◽  
Lepton Flavour

The latest results in the search for rare and exotic Higgs boson decays in proton-proton collision events collected with the CMS detector at the LHC are presented. The searches are performed for several decay modes of Higgs boson including H → X(X → 2ℓ)γ (X = Z, γ* and ℓ = e, μ), H → μμ=ee, invisible decays, lepton flavour violating decays and Higgs decay to light scalars or pseudo-scalars. No hint for new physics has been found from the analyzed results with the full LHC run-1 data collected during 2011 and 2012 at √s = 7-8 TeV and with the run-2 data at √s = 13 TeV collected during 2015 and 2016. Limits are set for all the searches which have been performed by CMS.

scholarly journals Search for type-III seesaw heavy leptons in dilepton final states in pp collisions at $$ \sqrt{s} = 13\,{\text {TeV}} $$ with the ATLAS detector

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Atlas Detector ◽  
Proton Collision ◽  
Final State ◽  
Proton Proton ◽  
Type Iii ◽  
Missing Transverse Momentum ◽  
Proton Proton Collision ◽  
Heavy Leptons ◽  
Two Jets

AbstractA search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV, corresponding to $$ 139\,{\text {fb}}^{-1} $$ 139 fb - 1 of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis focuses on the final state with two light leptons (electrons or muons) of different flavour and charge combinations, with at least two jets and large missing transverse momentum. No significant excess over the Standard Model expectation is observed. The results are translated into exclusion limits on heavy-lepton masses, and the observed lower limit on the mass of the type-III seesaw heavy leptons is 790 GeV at 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 dark matter in events with missing transverse momentum and a Higgs boson decaying into two photons in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Transverse Momentum ◽  
Atlas Detector ◽  
Proton Collision ◽  
Final State ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
Higgs Boson Decaying ◽  
Proton Proton Collision

Abstract A search for dark-matter particles in events with large missing transverse momentum and a Higgs boson candidate decaying into two photons is reported. The search uses 139 fb−1 of proton-proton collision data collected at $$ \sqrt{s} $$ s = 13 TeV with the ATLAS detector at the CERN LHC between 2015 and 2018. No significant excess of events over the Standard Model predictions is observed. The results are interpreted by extracting limits on three simplified models that include either vector or pseudoscalar mediators and predict a final state with a pair of dark-matter candidates and a Higgs boson decaying into two photons.

scholarly journals Reconstruction and identification of boosted di-τ systems in a search for Higgs boson pairs using 13 TeV proton-proton collision data in ATLAS

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Hadron Collider ◽  
Gluon Fusion ◽  
Mass Range ◽  
Proton Collision ◽  
Final State ◽  
Proton Proton ◽  
Scalar Resonance ◽  
Proton Proton Collision ◽  
A New Technique

Abstract In this paper, a new technique for reconstructing and identifying hadronically decaying τ+τ− pairs with a large Lorentz boost, referred to as the di-τ tagger, is developed and used for the first time in the ATLAS experiment at the Large Hadron Collider. A benchmark di-τ tagging selection is employed in the search for resonant Higgs boson pair production, where one Higgs boson decays into a boosted $$ b\overline{b} $$ b b ¯ pair and the other into a boosted τ+τ− pair, with two hadronically decaying τ-leptons in the final state. Using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of 13 TeV, the efficiency of the di-τ tagger is determined and the background with quark- or gluon-initiated jets misidentified as di-τ objects is estimated. The search for a heavy, narrow, scalar resonance produced via gluon-gluon fusion and decaying into two Higgs bosons is carried out in the mass range 1–3 TeV using the same dataset. No deviations from the Standard Model predictions are observed, and 95% confidence-level exclusion limits are set on this model.

scholarly journals Measurement of the Higgs Boson Mass in the H → ZZ∗→ 4ℓ and H → γγ Channels with s = 13TeV pp Collisions Using the ATLAS Detector

2018 ◽  
Vol 46 ◽  
pp. 1860052
Author(s):  
N. Bruscino
Keyword(s):  
Higgs Boson ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Atlas Detector ◽  
Boson Mass ◽  
Proton Collision ◽  
Proton Proton ◽  
Decay Channels ◽  
Mass Distributions ◽  
Center Of Mass Energy

The mass of the Higgs boson is measured in the [Formula: see text] and in the [Formula: see text] decay channels with [Formula: see text]fb[Formula: see text] of proton-proton collision data from the Large Hadron Collider at a center-of-mass energy of [Formula: see text] TeV recorded by the ATLAS detector in 2015 and 2016. The measured value in the [Formula: see text] channel is [Formula: see text]GeV, while the measured value in the [Formula: see text] channel is [Formula: see text]GeV. The two results have a compatibility of [Formula: see text]. The combined measurement from a simultaneous fit to the invariant mass distributions in the two channels is [Formula: see text]GeV.

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