Examinando por Autor "Zamora Saa, J. A."
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Ítem Combined Measurement of the Higgs Boson Mass from the Formula Presented and Formula Presented Decay Channels with the ATLAS Detector Using Formula Presented, 8, and 13 TeV Formula Presented Collision Data(American Physical Society, 2023-12) Filmer E.K.; Grant, C.M; ATLAS Collaboration; Kuleshov, S.; Olivares Pino, S. A.; Zamora Saa, J. A.A measurement of the mass of the Higgs boson combining the Formula Presented and Formula Presented decay channels is presented. The result is based on Formula Presented 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 Formula Presented. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics. © 2023 CERN, for the ATLAS Collaboration.Ítem Search for exclusive Higgs and Z boson decays to ωγ and Higgs boson decays to K⁎γ with the ATLAS detector(Elsevier B.V., 2023-12) Aad, G.; Abbott, B.; Abeling, K.; ATLAS Collaboration; Kuleshov, S.; Olivares Pino, S. A.; Zamora Saa, J. A.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. © 2023 The AuthorÍtem Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector(Institute for Ionics, 2023-08) Aad, G.; Abbott, B.; Abbott, D. C.; ATLAS Collaboration; Kuleshov, S.; Zamora Saa, J. A.A search for pair-produced vector-like quarks using events with exactly one lepton (e or μ), at least four jets including at least one b-tagged jet, and large missing transverse momentum is presented. Data from proton–proton collisions at a centre-of-mass energy of s= 13 TeV , recorded by the ATLAS detector at the LHC from 2015 to 2018 and corresponding to an integrated luminosity of 139 fb - 1 , are analysed. Vector-like partners T and B of the top and bottom quarks are considered, as is a vector-like X with charge + 5 / 3 , assuming their decay into a W, Z, or Higgs boson and a third-generation quark. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section of T and B quark pairs as a function of their mass are derived for various decay branching ratio scenarios. The strongest lower limits on the masses are 1.59 TeV assuming mass-degenerate vector-like quarks and branching ratios corresponding to the weak-isospin doublet model, and 1.47 TeV (1.46 TeV) for exclusive T→ Zt (B/ X→ Wt) decays. In addition, lower limits on the T and B quark masses are derived for all possible branching ratios. © 2023, The Author(s).