1,295 research outputs found

    Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

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    In the version of this article initially published, the ATLAS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article

    Search for the Exclusive W Boson Hadronic Decays W± → π±γ, W± → K±γ and W± → ρ±γ with the ATLAS Detector

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    A search for the exclusive hadronic decays W^{±}→π^{±}γ, W^{±}→K^{±}γ, and W^{±}→ρ^{±}γ is performed using up to 140 fb^{-1} of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of sqrt[s]=13 TeV. If observed, these rare processes would provide a unique test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders. Additionally, at future colliders, these decays could offer a new way to measure the W boson mass through fully reconstructed decay products. The search results in the most stringent upper limits to date on the branching fractions B(W^{±}→π^{±}γ)<1.9×10^{-6}, B(W^{±}→K^{±}γ)<1.7×10^{-6}, B(W^{±}→ρ^{±}γ)<5.2×10^{-6} at 95% confidence level

    Search for the Exclusive W Boson Hadronic Decays W±→π±γ , W±→K±γ and W±→ρ±γ with the ATLAS Detector

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    A search for the exclusive hadronic decays W± → π±γ, W± → K±γ, and W± → ρ±γ is performed using up to 140 fb−1 of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of √s = 13 TeV. If observed, these rare processes would provide a unique test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders. Additionally, at future colliders, these decays could offer a new way to measure the W boson mass through fully reconstructed decay products. The search results in the most stringent upper limits to date on the branching fractions B(W± → π±γ) &lt; 1.9 × 10−6, B(W± → K±γ) &lt; 1.7 × 10−6, B(W± → ρ±γ) &lt; 5.2 × 10−6 at 95% confidence level

    Search for exclusive Higgs and Z boson decays to ωγ and Higgs boson decays to K⁎γ with the ATLAS detector

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    Searches for the exclusive decays of the Higgs boson to an ω meson and a photon or a K⁎ meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for these decays, along with the analogous Z boson decay to an ω meson and a photon, are performed with a pp collision data sample corresponding to integrated luminosities of up to 134 fb−1 collected at s=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The obtained 95% confidence-level upper limits on the respective branching fractions are B(H→ωγ)<5.5×10−4, B(H→K⁎γ)<2.2×10−4 and B(Z→ωγ)<3.9×10−6. The limits for H→ωγ and Z→ωγ are 370 times and 140 times the Standard Model expected values, respectively. The result for Z→ωγ corresponds to a two-orders-of-magnitude improvement over the limit obtained by the DELPHI experiment at LEP

    Search for exclusive Higgs and ZZ boson decays to ωγ\omega\gamma and Higgs boson decays to KγK^{*}\gamma with the ATLAS detector

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    Searches for the exclusive decays of the Higgs boson to an ω\omega meson and a photon or a KK^{*} meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for these decays, along with the analogous ZZ boson decay to an ω\omega meson and a photon, are performed with a pppp collision data sample corresponding to integrated luminosities of up to 134 fb1^{-1} collected at s=13\sqrt{s}=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The obtained 95% confidence-level upper limits on the respective branching fractions are B(Hωγ)KmesonandaphotoncanprobeflavourconservingandflavourviolatingHiggsbosoncouplingstolightquarks,respectively.Searchesforthesedecays,alongwiththeanalogousZbosondecaytoanωmesonandaphoton,areperformedwithappcollisiondatasamplecorrespondingtointegratedluminositiesofupto134fb1collectedats=13TeVwiththeATLASdetectorattheCERNLargeHadronCollider.Theobtained95{\cal B}(H\rightarrow\omega\gamma)K⁎ meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for these decays, along with the analogous Z boson decay to an ω meson and a photon, are performed with a pp collision data sample corresponding to integrated luminosities of up to 134 fb−1 collected at s=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The obtained 95% confidence-level upper limits on the respective branching fractions are B(H→ωγ)&lt;5.5×10−4, B(H→K⁎γ)&lt;2.2×10−4 and B(Z→ωγ)&lt;3.9×10−6. The limits for H→ωγ and Z→ωγ are 370 times and 140 times the Standard Model expected values, respectively. The result for Z→ωγ corresponds to a two-orders-of-magnitude improvement over the limit obtained by the DELPHI experiment at LEP.Searches for the exclusive decays of the Higgs boson to an \omegamesonandaphotonora meson and a photon or a K^{*}mesonandaphotoncanprobeflavourconservingandflavourviolatingHiggsbosoncouplingstolightquarks,respectively.Searchesforthesedecays,alongwiththeanalogous meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for these decays, along with the analogous Zbosondecaytoan boson decay to an \omegamesonandaphoton,areperformedwitha meson and a photon, are performed with a ppcollisiondatasamplecorrespondingtointegratedluminositiesofupto134fb collision data sample corresponding to integrated luminosities of up to 134 fb^{-1}collectedat collected at \sqrt{s}=13TeVwiththeATLASdetectorattheCERNLargeHadronCollider.Theobtained95 TeV with the ATLAS detector at the CERN Large Hadron Collider. The obtained 95% confidence-level upper limits on the respective branching fractions are {\cal B}(H\rightarrow\omega\gamma)< 5.5\times 10^{-4},, {\cal B}(H\rightarrow K^{*}\gamma)< 2.2\times10^{-4}and and {\cal B}(Z\rightarrow \omega\gamma)<3.9\times 10^{-6}.Thelimitsfor. The limits for H\rightarrow \omega\gammaand and Z\rightarrow \omega\gammaare370timesand140timestheStandardModelexpectedvalues,respectively.Theresultfor are 370 times and 140 times the Standard Model expected values, respectively. The result for Z\rightarrow \omega\gamma$ corresponds to a two-orders-of-magnitude improvement over the limit obtained by the DELPHI experiment at LEP

    Precision measurement of the B0 meson lifetime using B0 → J/ψ K∗0 decays with the ATLAS detector

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    A measurement of the B0 meson lifetime using B0 → J/ψ K∗0 decays in data from 13 TeV proton–proton collisions with an integrated luminosity of 140 fb−1 recorded by the ATLAS detector at the LHC is presented. The measured effective lifetime is τ = 1.5053 ± 0.0012 (stat.) ± 0.0035 (syst.) ps. The average decay width extracted from the effective lifetime, using parameters from external sources, is Gamma_d = 0.6639 ± 0.0005 (stat.) ± 0.0016 (syst.) ± 0.0038 (ext.) ps−1, where the uncertainties are statistical, systematic and from external sources. The earlier ATLAS measurement of &#x5;s in the B0 s → J/ψφ decay was used to derive a value for the ratio of the average decay widths Gamma_d and Gamma_s for B0 and B0s mesons respectively, of Gamma_d/Gamma_s = 0.9905±0.0022 (stat.)±0.0036 (syst.)±0.0057 (ext.). The measured lifetime, average decay width and decay width ratio are in agreement with theoretical predictions and with measurements by other experiments. This measurement provides the most precise result of the effective lifetime of the B0 meson to date

    Measurement of muon pairs produced via γγ scattering in nonultraperipheral Pb + Pb collisions at √sNN = 5.02 TeV with the ATLAS detector

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    Results of a measurement of dimuon photoproduction in nonultraperipheral Pb + Pb collisions at √sNN = 5.02 TeV are presented. Themeasurement uses ATLAS data from the 2015 and 2018 Pb + Pb data-taking periods at the LHC with an integrated luminosity of 1.94 nb.1. The γγ → μ+ μ- pairs are identified via selections on pair momentum asymmetry and acoplanarity. Differential cross sections for dimuon production are measured in different centrality, average muon momentum, and pair rapidity intervals as functions of acoplanarity and k⊥, the transverse momentum kick of one muon relative to the other. Measurements are also made as a function of the rapidity separation of the muons and the angle of the muon pair relative to the second-order event plane to test whether magnetic fields generated in the quark-gluon plasma affect the measured muons. A prior observation of a centrality-dependent broadening of the acoplanarity distribution is confirmed. Furthermore, the improved precision of the measurement reveals a depletion in the number of pairs having small acoplanarity or k⊥ values in more central collisions. The acoplanarity distributions in a given centrality interval are observed to vary with the mean pT of the muons in the pair, but the k⊥ distributions do not. Comparisons with recent theoretical predictions are made. The predicted trends associated with effects of magnetic fields on the dimuons are not observed

    Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

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    Third order non linear optical properties of ZnO:Al thin films prepared by spray pyrolysis

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    In this study, zinc oxide (ZnO) and aluminium doped zinc oxide (ZnO:Al) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 450degC. X-ray diffraction (XRD), scanning electron microscopy (SEM) and third harmonic generation (THG) are used to characterize their structure , morphology and nonlinear optical properties as a function of Al concentration (0, 3, 5, 7 at %). The intensity of third order non linear optical susceptibility increase by incorporation of aluminium. A strong value of susceptibility chi(3) was found for films with a good crystallinity

    Measurement of muon pairs produced via γγ scattering in nonultraperipheral Pb+Pb collisions at √sNN = 5.02 TeV with the ATLAS detector

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    Results of a measurement of dimuon photoproduction in nonultraperipheral Pb + Pb collisions at √ s N N = 5.02 TeV are presented. The measurement uses ATLAS data from the 2015 and 2018 Pb + Pb data-taking periods at the LHC with an integrated luminosity of 1.94 nb − 1 . The γ γ → μ + μ − pairs are identified via selections on pair momentum asymmetry and acoplanarity. Differential cross sections for dimuon production are measured in different centrality, average muon momentum, and pair rapidity intervals as functions of acoplanarity and k ⊥ , the transverse momentum kick of one muon relative to the other. Measurements are also made as a function of the rapidity separation of the muons and the angle of the muon pair relative to the second-order event plane to test whether magnetic fields generated in the quark-gluon plasma affect the measured muons. A prior observation of a centrality-dependent broadening of the acoplanarity distribution is confirmed. Furthermore, the improved precision of the measurement reveals a depletion in the number of pairs having small acoplanarity or k ⊥ values in more central collisions. The acoplanarity distributions in a given centrality interval are observed to vary with the mean p T of the muons in the pair, but the k ⊥ distributions do not. Comparisons with recent theoretical predictions are made. The predicted trends associated with effects of magnetic fields on the dimuons are not observed
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