ORCID Profile
0000-0002-5092-7213
Current Organisation
Université catholique de Louvain
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Publisher: Springer Science and Business Media LLC
Date: 08-2020
Abstract: A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at $$ \\sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 35 . 9 fb − 1 , collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H → aa → μμττ , and considers pseudoscalar masses in the range 3 . 6 m a 21 GeV. Because of the large mass difference between the H and the a bosons and the small masses of the a boson decay products, both the μμ and the ττ pairs have high Lorentz boost and are collimated. The ττ reconstruction efficiency is increased by modifying the standard technique for hadronic τ lepton decay reconstruction to account for a nearby muon. No significant signal is observed. Model-independent limits are set at 95% confidence level, as a function of m a , on the branching fraction (ℬ) for H → aa → μμττ , down to 1 . 5 (2 . 0) × 10 − 4 for m H = 125 (300) GeV. Model-dependent limits on ℬ(H → aa) are set within the context of two Higgs doublets plus singlet models, with the most stringent results obtained for Type-III models. These results extend current LHC searches for heavier a bosons that decay to resolved lepton pairs and provide the first such bounds for an H boson with a mass above 125 GeV.
Publisher: American Physical Society (APS)
Date: 07-10-2020
Publisher: American Physical Society (APS)
Date: 12-08-2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: IOP Publishing
Date: 28-02-2020
Publisher: Elsevier BV
Date: 07-2020
Publisher: Springer Science and Business Media LLC
Date: 11-2020
Abstract: Decays of the 125 GeV Higgs boson into a Z boson and a ρ 0 (770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at $$ \\sqrt{s} $$ s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb − 1 . Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels.
Publisher: Springer Science and Business Media LLC
Date: 09-2020
Abstract: A search for new physics in events with two highly Lorentz-boosted Z bosons and large missing transverse momentum is presented. The analyzed proton-proton collision data, corresponding to an integrated luminosity of 137 fb − 1 , were recorded at $$ \\sqrt{s} $$ s = 13 TeV by the CMS experiment at the CERN LHC. The search utilizes the substructure of jets with large radius to identify quark pairs from Z boson decays. Backgrounds from standard model processes are suppressed by requirements on the jet mass and the missing transverse momentum. No significant excess in the event yield is observed beyond the number of background events expected from the standard model. For a simplified supersymmetric model in which the Z bosons arise from the decay of gluinos, an exclusion limit of 1920 GeV on the gluino mass is set at 95% confidence level. This is the first search for beyond-standard-model production of pairs of boosted Z bosons plus large missing transverse momentum.
Publisher: American Physical Society (APS)
Date: 05-10-2020
No related grants have been discovered for Sophie Wuyckens.