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-o...
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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)<1.9×10−6, B(W±→K±γ)<1.7×10−6, B(W±→ρ±γ)<5.2×10−6 at 95% confidence level.
A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to 139 fb−1 of pp collision data at s=13 TeV recorded with the ATLAS detector at the LHC. The combination include...
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A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to 139 fb−1 of pp collision data at s=13 TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: bb¯bb¯, bb¯τ+τ−, and bb¯γγ. No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV–5 TeV. The observed (expected) limits are in the range 0.96–600 fb (1.2–390 fb). The limits are interpreted in the type-I two-Higgs-doublet model and the minimal supersymmetric standard model, and constrain parameter space not previously excluded by other searches.
Angular correlations between heavy quarks provide a unique probe of the quark-gluon plasma created in ultrarelativistic heavy-ion collisions. Results are presented of a measurement of the azimuthal angle correlations ...
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Angular correlations between heavy quarks provide a unique probe of the quark-gluon plasma created in ultrarelativistic heavy-ion collisions. Results are presented of a measurement of the azimuthal angle correlations between muons originating from semileptonic decays of heavy quarks produced in 5.02 TeV Pb+Pb and pp collisions at the LHC. The muons are measured with transverse momenta and pseudorapidities satisfying pTμ>4 GeV and |ημ|<2.4, respectively. The distributions of azimuthal angle separation Δϕ for muon pairs having pseudorapidity separation |Δη|>0.8, are measured in different Pb+Pb centrality intervals and compared to the same distribution measured in pp collisions at the same center-of-mass energy. Results are presented separately for muon pairs with opposite-sign charges, same-sign charges, and all pairs. A clear peak is observed in all Δϕ distributions at Δϕ∼π, consistent with the parent heavy-quark pairs being produced via hard-scattering processes. The widths of that peak, characterized using Cauchy-Lorentz fits to the Δϕ distributions, are found to not vary significantly as a function of Pb+Pb collision centrality and are similar for pp and Pb+Pb collisions. This observation will provide important constraints on theoretical descriptions of heavy-quark interactions with the quark-gluon plasma.
Presented is the search for anomalous Higgs boson decays into two axion-like particles (ALPs) using the full Run 2 data set of $$140\,\text {fb}^{-1}$$ of proton-proton collisions at a centre-of-mass energy o...
Presented is the search for anomalous Higgs boson decays into two axion-like particles (ALPs) using the full Run 2 data set of $$140\,\text {fb}^{-1}$$ of proton-proton collisions at a centre-of-mass energy of $$13\,\text {TeV}$$ recorded by the ATLAS experiment. The ALPs are assumed to decay into two photons, providing sensitivity to recently proposed models that could explain the $$(g-2)_\mu $$ discrepancy. This analysis covers an ALP mass range from 100 to $$62\,\text {GeV}$$ and ALP-photon couplings in the range $$10^{-7}\,\text {TeV}^{-1}
Despite substantial declines since 2000, lower respiratory infections (LRIs), diarrhoeal diseases, and malaria remain among the leading causes of nonfatal and fatal disease burden for children under 5 years of age (un...
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There are several ways to deal with security issues of confidential data sent via the internet, including using cryptographic techniques and steganography. Steganography is the science and art of concealing informatio...
There are several ways to deal with security issues of confidential data sent via the internet, including using cryptographic techniques and steganography. Steganography is the science and art of concealing information / messages in a media in such a way that its existence is not detected by other parties who are not entitled to the information. Instead, cryptography disguises the meaning of a message, but does not hide that there is a message because the file looks suspicious. The Steganography technique used here was End Of File (EOF). The EOF technique described how to add data or files at the end of the image file. For this technique, the size of data or files that will be hidden could be larger than the size of the image file. The hidden data will be inserted at the end of the file so that it will not affect the image. This steganography application is also equipped with a cryptographic function Data Encryption Standard (DES) at the time of insertion of data that functions as a generator code and encrypts data, so that the security of a data in the file is more protected and protected from those who are not entitled to know the data.
The inclusive Higgs boson production cross-section is measured in the di-photon and the $$ZZ^* \rightarrow 4 \ell $$ decay channels using 31.4 and 29.0 fb $$^{-1}$$ of pp collision data respectively, collecte...
The inclusive Higgs boson production cross-section is measured in the di-photon and the $$ZZ^* \rightarrow 4 \ell $$ decay channels using 31.4 and 29.0 fb $$^{-1}$$ of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of $$\sqrt{s}=13.6$$ $$\text {TeV}$$ . To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are $$\sigma _{\textrm{fid},\gamma \gamma } = $$ $$76^{+14}_{-13}$$ fb, and $$\sigma _{\textrm{fid},4 \ell } =$$ $$2.80\, \pm \, 0.74$$ fb, in agreement with the corresponding Standard Model predictions of $$67.6 \pm 3.7 $$ fb and $$3.67 \pm 0.19 $$ fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of $$\sigma (pp \rightarrow H) = 67^{+12}_{-11}$$ pb and $$46 \pm 12$$ pb at 13.6 $$\text {TeV}$$ from the di-photon and $$ZZ^* \rightarrow 4 \ell $$ measurements respectively. The two measurements are combined into a total cross-section measurement of $$\sigma (pp \rightarrow H)= 58.2 \pm 8.7$$ pb, to be compared with the Standard Model prediction of $$\sigma (pp \rightarrow H)_\textrm{SM} = 59.9 \pm 2.6 $$ pb.
A search for leptoquark pair production decaying into $$te^- \bar{t}e^+$$ or $$t\mu ^- \bar{t}\mu ^+$$ in final states with multiple leptons is presented. The search is based on a dataset of pp collisions at $$\sqrt{s...
A search for leptoquark pair production decaying into $$te^- \bar{t}e^+$$ or $$t\mu ^- \bar{t}\mu ^+$$ in final states with multiple leptons is presented. The search is based on a dataset of pp collisions at $$\sqrt{s}=13~\text {TeV} $$ recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb $$^{-1}$$ . Four signal regions, with the requirement of at least three light leptons (electron or muon) and at least two jets out of which at least one jet is identified as coming from a b-hadron, are considered based on the number of leptons of a given flavour. The main background processes are estimated using dedicated control regions in a simultaneous fit with the signal regions to data. No excess above the Standard Model background prediction is observed and 95% confidence level limits on the production cross section times branching ratio are derived as a function of the leptoquark mass. Under the assumption of exclusive decays into $$te^{-}$$ ( $$t\mu ^{-}$$ ), the corresponding lower limit on the scalar mixed-generation leptoquark mass $$m_{\textrm{LQ}_{\textrm{mix}}^{\textrm{d}}}$$ is at 1.58 (1.59) TeV and on the vector leptoquark mass $$m_{{\tilde{U}}_1}$$ at 1.67 (1.67) TeV in the minimal coupling scenario and at 1.95 (1.95) TeV in the Yang–Mills scenario.
Measurements of the differential production cross-sections of prompt and non-prompt $$J/\psi $$ and $$\psi (2{\textrm{S}})$$ mesons with transverse momenta between 8 and 360 GeV and rapidity in the range $$|y...
Measurements of the differential production cross-sections of prompt and non-prompt $$J/\psi $$ and $$\psi (2{\textrm{S}})$$ mesons with transverse momenta between 8 and 360 GeV and rapidity in the range $$|y|<2$$ are reported. Furthermore, measurements of the non-prompt fractions of $$J/\psi $$ and $$\psi (2{\textrm{S}})$$ , and the prompt and non-prompt $$\psi (2{\textrm{S}})$$ -to- $$J/\psi $$ production ratios, are presented. The analysis is performed using 140 fb $$^{-1}$$ of $$\sqrt{s}=13$$ TeV pp collision data recorded by the ATLAS detector at the LHC during the years 2015–2018.
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