The Hyades Kinematical Structure with Gaia Era

268-273In this work, we have improved the Hyades members with crossmatch between Hipparcos and the recent Gaia EDR3 source, the obtained members with highly probable are about 186 candidates. Considering the classical convergent point and depending on proper motions and radial velocities, we have computed the apex position A, D 93. 36 0. 046, 7. 43 0. 713 which is in line with others. The internal structural parameters of the Hyades open cluster are demonstrated here with space spatial velocities; i.e., , V, V; km s (-5.97±0.41, 45.54±6.75, 5.52±0.43) and , V, W ; km s (-42.11±6.50, -19.09±4.37, -1.32±0.44) and on basis of matrix elements μ, the Velocity Ellipsoid Parameters were achieved, e.g., λ, λ, λ; km s 2137.36 23.12, 6.06 0.41, 2.53 0.63 and σ, σ, σ; km s 46.23 6.80, 2.47 0.64, 1.59 0.80. For the observational quantities, we have deduced a correlation coefficient of about 0.83 for the kinematical property of proper motions on both sides μ cos δ , μ; mas yr and the physical property with the angular distances λ from the vertex, and those prove that the attributes are completely related linearly

The Hyades Kinematical Structure with Gaia Era

In this work, we have improved the Hyades members with crossmatch between Hipparcos and the recent Gaia EDR3 source, the obtained members with highly probable are about 186 candidates. Considering the classical convergent point and depending on proper motions and radial velocities, we have computed the apex position (A_cp,D_cp )=(〖93〗^o.36±0^o.046,7^o.43±0^o.713) which is in line with others. The internal structural parameters of the Hyades open cluster are demonstrated here with space spatial velocities; i.e., (V ̅_X,V ̅_Y,V ̅_Z; km s^(-1) )=(-5.97±0.41, 45.54±6.75, 5.52±0.43) and (U ̅,V ̅,W ̅; km s^(-1) )= (-42.11±6.50, -19.09±4.37, -1.32±0.44) and on basis of matrix elements (μ_ij ), the Velocity Ellipsoid Parameters were achieved, e.g., (λ_1,λ_1,λ_1; km s^(-1) )=(2137.36 ± 23.12,6.06 ± 0.41,2.53 ± 0.63) and (σ_1,σ_1,σ_1; km s^(-1) )=(46.23 ± 6.80,2.47 ± 0.64,1.59 ± 0.80). For the observational quantities, we have deduced a correlation coefficient of about ≈0.83 for the kinematical property of proper motions on both sides (μ_α cos⁡δ,μ_δ; mas yr^(-1) ) and the physical property with the angular distances (λ) from the vertex, and those prove that the attributes are completely related linearly

Observation of WWγ\gamma production and search for Hγ\gamma production in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceThe observation of WW$\gamma$ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138 fb$^{-1}$ is presented. The observed (expected) significance is 5.6 (4.7) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WW$\gamma$ is 6.0 $\pm$ 0.8 (stat) $\pm$ 0.7 (syst) $\pm$ 0.6 (modeling) fb, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks

Luminosity determination using Z boson production at the CMS experiment

International audienceThe measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton-proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV. Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same dataset, in small intervals of 2 pb$^{-1}$ of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity

Search for direct production of GeV-scale resonances decaying to a pair of muons in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search for direct production of low-mass dimuon resonances is performed using $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the CMS experiment during the 2017-2018 operation of the CERN LHC with an integrated luminosity of 96.6 fb$^{-1}$. The search exploits a dedicated high-rate trigger stream that records events with two muons with transverse momenta as low as 3 GeV but does not include the full event information. The search is performed by looking for narrow peaks in the dimuon mass spectrum in the ranges of 1.1-2.6 GeV and 4.2-7.9 GeV. No significant excess of events above the expectation from the standard model background is observed. Model-independent limits on production rates of dimuon resonances within the experimental fiducial acceptance are set. Competitive or world's best limits are set at 90% confidence level for a minimal dark photon model and for a scenario with two Higgs doublets and an extra complex scalar singlet (2HDM+S). Values of the squared kinetic mixing coefficient $\varepsilon^2$ in the dark photon model above 10$^{-6}$ are excluded over most of the mass range of the search. In the 2HDM+S, values of the mixing angle $\sin(\theta_\text{H})$ above 0.08 are excluded over most of the mass range of the search with a fixed ratio of the Higgs doublets vacuum expectation $\tan\beta$ = 0.5

Search for inelastic dark matter in events with two displaced muons and missing transverse momentum in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search for dark matter in events with a displaced muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138 fb$^{-1}$ of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section $\sigma$(pp $\to$ A' $\to$$\chi_1$$\chi_2$) and the decay branching fraction $\mathcal{B}$($\chi_2$$\to$$\chi_1\mu^+\mu^-$), where A' is a dark photon and $\chi_1$ and $\chi_2$ are dark matter states with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter

Measurement of the Higgs boson production via vector boson fusion and its decay into bottom quarks in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA measurement of the Higgs boson (H) production via vector boson fusion (VBF) and its decay into a bottom quark-antiquark pair ($\mathrm{b\bar{b}}$) is presented using proton-proton collision data recorded by the CMS experiment at $\sqrt{s}$ = 13 TeV and corresponding to an integrated luminosity of 90.8 fb$^{-1}$. Treating the gluon-gluon fusion process as a background and constraining its rate to the value expected in the standard model (SM) within uncertainties, the signal strength of the VBF process, defined as the ratio of the observed signal rate to that predicted by the SM, is measured to be $\mu^\text{qqH}_\mathrm{Hb\bar{b}}$ = 1.01$^{+0.55}_{-0.46}$. The VBF signal is observed with a significance of 2.4 standard deviations relative to the background prediction, while the expected significance is 2.7 standard deviations. Considering inclusive Higgs boson production and decay into bottom quarks, the signal strength is measured to be $\mu^\text{incl.}_\mathrm{Hb\bar{b}}$ = 0.99$^{+0.48}_{-0.41}$, corresponding to an observed (expected) significance of 2.6 (2.9) standard deviations

Observation of new structure in the J/ψ\psiJ/ψ\psi mass spectrum in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search is reported for near-threshold structures in the J/$\psi$J/$\psi$ invariant mass spectrum produced in proton-proton collisions at $\sqrt{s}$ = 13 TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135 fb$^{-1}$. A new structure is observed with a significance above 5 standard deviations at a mass of 6552 $\pm$ 10 (stat) $\pm$ 12 (syst) MeV. Another structure with even higher significance is found at a mass of 6927 $\pm$ 9 (stat) $\pm$ 4 (syst) MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.1 standard deviations, is found at a mass of 7287$^{+20}_{-18}$ (stat) $\pm$ 5 (syst) MeV. The masses and significances are obtained in a model without considering possible quantum mechanical interference between the resonances. Incorporating this interference provides a better description of the mass spectrum between the resonances and shifts the measured masses by up to 150 MeV

Search for the lepton-flavor violating decay of the Higgs boson and additional Higgs bosons in the eμ\mu final state in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search for the lepton-flavor violating decay of the Higgs boson and potential additional Higgs bosons with a mass in the range 110-160 GeV to an e$^{\pm}\mu^{\mp}$ pair is presented. The search is performed with a proton-proton collision data set at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. No excess is observed for the Higgs boson. The observed (expected) upper limit on the e$^{\pm}\mu^{\mp}$ branching fraction for it is determined to be 4.4 (4.7) $\times$ 10$^{-5}$ at 95% confidence level, the most stringent limit set thus far from direct searches. The largest excess of events over the expected background in the full mass range of the search is observed at an e$^{\pm}\mu^{\mp}$ invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations