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Special EPE seminar: Yue Xu
Description
Title: Search for heavy Higgs bosons in same-sign two-lepton final states and observation of an excess of di-charmonium events with the ATLAS detector
Abstract:
This talk includes two parts. The first part will present a search for heavy Higgs bosons produced in association with a vector boson and decaying into a pair of vector bosons in final states with two leptons of the same electric charge, missing transverse momentum and jets. The observed data are in agreement with Standard Model background expectations. The results are interpreted using higher-dimensional operators in an effective field theory. Upper limits on the production cross-section are calculated at 95\% confidence level as a function of the heavy Higgs boson's mass and coupling strengths to vector bosons.
The second part will present the search of potential $cc\bar{c}\bar{c}$ tetraquarks decaying into a pair of charmonium states in the four-muon final state. Two decay channels, $J/\psi+J/\psi \rightarrow 4\mu$ and $J/\psi+\psi(2S) \rightarrow 4\mu$, are studied.
Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-$J/\psi$ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the $J/\psi$+$\psi$(2S) channel.
Bio:
Yue Xu obtained her Ph.D. under the supervision of Prof. Xin Chen from the department of Physics at Tsinghua University in 2022, and currently a post-doc at Tsinghua University. She contributed to the search of generic heavy Higgs bosons and the observation of di-charmonium excesses in the four-muon final state, with a leading role as analysis contact and contact editor. She currently focuses on searching for singly and doubly charged Higgs bosons, and full-charm tetraquarks with the $4\mu+2\pi$ final state. She is also working on the electronic tests and cold noise studies with strip modules for the ATLAS ITk project.
