Higgs boson production via gluon-gluon fusion and vector-boson fusion in proton-proton collisions is measured in the H→WW*→eνμν decay channel. The Large Hadron Collider delivered proton-proton collisions at a cen...
详细信息
Higgs boson production via gluon-gluon fusion and vector-boson fusion in proton-proton collisions is measured in the H→WW*→eνμν decay channel. The Large Hadron Collider delivered proton-proton collisions at a center-of-mass energy of 13 TeV between 2015 and 2018, which were recorded by the ATLAS detector, corresponding to an integrated luminosity of 139 fb−1. The total cross sections for Higgs boson production by gluon-gluon fusion and vector-boson fusion times the H→WW* branching ratio are measured to be 12.0±1.4 and 0.75 −0.16+0.19 pb, respectively, in agreement with the Standard Model predictions of 10.4±0.6 and 0.81±0.02 pb. Higgs boson production is further characterized through measurements of Simplified Template Cross Sections in a total of 11 kinematic fiducial regions.
A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139 fb−1 of proton-proton collision data at s=13 TeV collected by the ATLAS detector at the L...
详细信息
A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139 fb−1 of proton-proton collision data at s=13 TeV collected by the ATLAS detector at the LHC. The optimal observable method is used to probe the CP structure of interactions between the Higgs boson and electroweak gauge bosons, as described by an effective field theory. No sign of CP violation is observed in the data. Constraints are set on the parameters describing the strength of the CP-odd component in the coupling between the Higgs boson and the electroweak gauge bosons in two effective field theory bases: d˜ in the HISZ basis and cHW˜ in the Warsaw basis. The results presented are the most stringent constraints on CP violation in the coupling between Higgs and weak bosons. The 95% C.L. constraint on d˜ is derived for the first time and the 95% C.L. constraint on cHW˜ has been improved by a factor of 5 compared to the previous measurement.
A search is presented for displaced production of Higgs bosons or Z bosons, originating from the decay of a neutral long-lived particle (LLP) and reconstructed in the decay modes H→γγ and Z→ee. The analysis uses t...
详细信息
A search is presented for displaced production of Higgs bosons or Z bosons, originating from the decay of a neutral long-lived particle (LLP) and reconstructed in the decay modes H→γγ and Z→ee. The analysis uses the full Run 2 dataset of proton-proton collisions delivered by the LHC at an energy of s=13 TeV between 2015 and 2018 and recorded by the ATLAS detector, corresponding to an integrated luminosity of 139 fb−1. Exploiting the capabilities of the ATLAS liquid argon calorimeter to precisely measure the arrival times and trajectories of electromagnetic objects, the analysis searches for the signature of pairs of photons or electrons which arise from a common displaced vertex and which arrive after some delay at the calorimeter. The results are interpreted in a gauge-mediated supersymmetry breaking model with pair-produced Higgsinos that decay to LLPs, and each LLP subsequently decays into either a Higgs boson or a Z boson. The final state includes at least two particles that escape direct detection, giving rise to missing transverse momentum. No significant excess is observed above the background expectation. The results are used to set upper limits on the cross section for Higgsino pair production, up to a χ˜10 mass of 369 (704) GeV for decays with 100% branching ratio of χ˜10 to Higgs (Z) bosons for a χ˜10 lifetime of 2 ns. A model-independent limit is also set on the production of pairs of photons or electrons with a significant delay in arrival at the calorimeter.
We infer the mean optical depth of a sample of optically selected galaxy clusters from the Dark Energy Survey via the pairwise kinematic Sunyaev-Zel’dovich (KSZ) effect. The pairwise KSZ signal between pairs of clust...
详细信息
We infer the mean optical depth of a sample of optically selected galaxy clusters from the Dark Energy Survey via the pairwise kinematic Sunyaev-Zel’dovich (KSZ) effect. The pairwise KSZ signal between pairs of clusters drawn from the Dark Energy Survey Year-3 cluster catalog is detected at 4.1σ in cosmic microwave background temperature maps from two years of observations with the SPT-3G camera on the South Pole Telescope. After cuts, there are 24,580 clusters in the ∼1,400 deg2 of the southern sky observed by both experiments. We infer the mean optical depth of the cluster sample with two techniques. The optical depth inferred from the pairwise KSZ signal is τ¯e=(2.97±0.73)×10−3, while that inferred from the thermal SZ signal is τ¯e=(2.51±0.55stat±0.15syst)×10−3. The two measures agree at 0.6σ. We perform a suite of systematic checks to test the robustness of the analysis.
A measurement of the mass of the Higgs boson combining the H→ZZ*→4ℓ and H→γγ decay channels is presented. The result is based on 140 fb−1 of proton-proton collision data collected by the ATLAS detector during LH...
详细信息
A measurement of the mass of the Higgs boson combining the H→ZZ*→4ℓ and H→γγ decay channels is presented. The result is based on 140 fb−1 of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.09(stat)±0.06(syst)=125.11±0.11 GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.
Nuclear Astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper ...
详细信息
This paper presents a measurement of fiducial and differential cross-sections for $$W^{+}W^{-}$$ production in proton–proton collisions at $$\sqrt{s}=13$$ TeV with the ATLAS experiment at the Large Hadron C...
This paper presents a measurement of fiducial and differential cross-sections for $$W^{+}W^{-}$$ production in proton–proton collisions at $$\sqrt{s}=13$$ TeV with the ATLAS experiment at the Large Hadron Collider using a dataset corresponding to an integrated luminosity of 139 fb $$^{-1}$$ . Events with exactly one electron, one muon and no hadronic jets are studied. The fiducial region in which the measurements are performed is inspired by searches for the electroweak production of supersymmetric charginos decaying to two-lepton final states. The selected events have moderate values of missing transverse momentum and the ‘stransverse mass’ variable $$m_{\textrm{T2}}$$ , which is widely used in searches for supersymmetry at the LHC. The ranges of these variables are chosen so that the acceptance is enhanced for direct $$W^{+}W^{-}$$ production and suppressed for production via top quarks, which is treated as a background. The fiducial cross-section and particle-level differential cross-sections for six variables are measured and compared with two theoretical SM predictions from perturbative QCD calculations.
Forecasting has always been at the forefront of decision making and planning. The uncertainty that surrounds the future is both exciting and challenging, with individuals and organisations seeking to minimise risks an...
详细信息
The last decade has seen unprecedented effort in dark matter model building at all mass scales coupled with the design of numerous new detection strategies. Transformative advances in quantum technologies have led to ...
详细信息
暂无评论